NIMBL RULES
Updated: April 2025
NI-MBL House Rules always take precedence over MLB Rules. The Northern Illinois – Men’s Baseball League (NI-MBL) will be referred to within these rules as the “League”. Where so and when so done, “League” is synonymous with our name, the Northern Illinois Men’s Baseball League (NI-MBL).
Uniforms, Helmets, Baseballs & Other Equipment
1. All teams must have full baseball uniforms consisting of caps, numbered baseball jerseys, baseball pants and belt. Each player’s uniform must be of similar design to his teammate’s uniforms. Teams having sponsorship will be allowed the sponsor’s name on a patch or uniform shirt.
2. Baseballs. 21s teams will each bring three (3) baseball balls to each game; each 35s and 48s team will bring a minimum of two (2) balls to each game. Only baseballs provided by the local league are allowed.
Wilson a1010 -or- Pro Nine PRO NFHS baseballs.
3. Bats. Wood and metal bats are allowed:
4. Baseball Shoes. Metal cleats are permitted.
5. Baseball Gloves. No size restrictions.
Teams, Players and Lineups
1. League Age Requirements. A player is eligible to participate in an official league sanctioned game if they are 21, 35, or 48 -- age division dependent -- within the season's calendar year.
2. Rosters. Unless the league offers a "team exception" team rosters must be submitted to the league by a date determined at “Winter Meetings”.
3. Waivers. Before playing in any NIMBL game, player waivers MUST BE COMPLETED by each player in order to play.
4. Scorebooks. Last names should be used to allow for proper player identification.
5. Start of the game. A team must have 8 players for an official game and/or may borrow a player from an opposing team with the opposing manager’s consent and/or may borrow a player from another team, also with the opposing manager’s consent. If the team’s 9th player arrives after the start of the game, the borrowed player reverts back to his team.
6. Emergency Players. Can only be called upon if a team is at 9 or less players; he must at maximum be the 10th and last player rostered for that game. For the 35’s and 48’s, the only exception with opposing manager approval is when a called upon extra emergency player shows up with 10 players in attendance.
The team manager must notify NI-MBL of their desire to add an “Emergency Player” for each game there is needed. Send an email to admin@nimabl.com with details of the situation. There are no guarantees of emergency player approval especially in instances of continued abuse/overuse of emergency players. Emergency Players are a game- playing solution not a game strategy.
7. Short players and can’t play the game… Forfeit. Two forfeits by any team could mean immediate expulsion from the “League” with no money refunded to the team. There will be a fine of $50 for each forfeit; subject to review by the “League”. After review, a fine may be reduced or waived. If the fines are not paid by the play-offs, a team will not be eligible for play- off play. Teams must notify league. Send an email to admin@nimabl.com with details of the situation
8. A team manager may bat as many players as he desires, with a minimum of 10 (subject to the number of players available, if less than 10). Batters cannot be deleted or skipped over, regardless of their batting position or when they were added during the game. If a team has only 9 (nine) players and therefore bats only 9, the opposing team will have the option of batting 9 as well. If a team has more than 9 players and still only bats nine, they will be assessed an out each time the 10th batting position is skipped. Batting only 9 players is NOT a protestable offense.
9. A manager may add batters to the bottom of the lineup at any time, but if a batter is pinch hit or run for the player may not re-enter the game as a hitter but may remain in the game as a fielder or pitcher. Added players to the bottom of the lineup may be added as individual hitters or as A/B. Each team has a hitting and a defensive lineup that are independent of each other. Players may play in either lineup or both.
10. A team MAY declare at the time that lineups are exchanged prior to the start of play that any batting order position (i.e. 1-2-9-10 can be occupied by two (2) players in each such batting position. That is, 2A/2B, 9A/9B, 11A/11B etc. The first time that an A/B position gets to bat, “A” would hit and the next time, B would be up. Then A hits the third time this spot in the order comes up, and so on, alternating between these two players throughout the game. Once a team declares the use of this A/B system, it must continue using it for the remainder of the game. Hitters in the A/B position may be pinch hit for, just as any other player.
11. All teams must announce all offensive additions, substitutions, and/or changes to the home plate umpire AND opposing team manager and/or scorekeeper. Only after this has been done will the added player be deemed a legal substitution.
12. If a team fails to announce an offensive addition/change, the player will be called out as soon as he occupies the batter’s box and the lineup will revert back to the lineup in effect prior to the player entering the game. The unannounced player will not have officially entered the offensive lineup and is therefore still available offensively even though an out has been assessed.
13. If a player is forced to leave a game due to an obvious injury, a reserve player, not previously entered into the game as a hitter, can hit in the replaced hitter’s place. If there are no reserves who can replace the individual, the spot is skipped and all hitters below that position move up. NO OUT will be assessed at any time. KEY PHRASE: “OBVIOUS INJURY.” For ejections, an out is assessed the first time that batting position comes up, then that spot is skipped without penalty for the remainder of the game.
14. No “out” penalty for players who have to leave a game early, per opposing MGRs approval. A player who has to leave a game early may do so without his team having to take the penalty of out when his turn comes up in the batting order. However, pre-game notification IS REQUIRED; the manager whose player is leaving early, must inform the opposing manager prior to the start of the game. The umpire does not need to be notified; but as a courtesy you should inform the umpire. If an opposing manager is not notified of a player’s early departure, it will be left to the discretion of the opposing manager, based on circumstances, if an out will or won’t be taken for the leaving player’s next at bat.
15. All players may be substituted for defensively, at any time, without affecting the player’s offensive status in the line-up. If the STARTING pitcher is removed, he may re-enter to pitch only one time during the course of the game, but not in the same inning. The removed pitcher may play any other position after being removed or no position at all. The re-entering of a STARTING pitcher can only be done once a game.
16. No player may switch teams without the consent of both managers and the league president. If this does not meet with approval, the player must sit out one full season from competition. In the event a team disbands during the season or at season’s conclusion, all players will become automatic free agents and will be permitted to play for any desired team. If a player is not invited back by his manager, he must be given his release so that he may go to the team of his choosing or re-enter the draft. If a player is invited back to play and he desires not to play for his former team and cannot be successfully traded, he must sit out one full season.
17. In the event a player wishes to leave his existing team and form a new team, he may do so. No other player can be taken from the existing team without the consent of the existing team’s manager. No other players may be taken from any other team without that team’s manager’s approval.
18. New Players: The league can assist in player placement to teams of all new players who have contacted the league in response to advertising or who have been referred to the league by any means. A player who has not played in any league game in either the current or previous year shall be regarded as a new player. A new player acquired by a team through that team’s own recruiting efforts shall be subject to the control of the team and not the league.
General “League” Rules
1. Rain Outs / Umpire Situations. NI-MBL does not maintain a rain-out or game status hotline. Managers must communicate with their players directly regarding game status. Rainouts must be called in directly to umpires or the umpire assignor at least two (2) hours before scheduled game time. Managers will use MGRs toolbox on league website to obtain umpire information.
2. Score Reporting and Stats. Scores are to be reported online. You will have ten (11) days to enter scores and stats and then the game will lock. Teams must input players in attendance of game under the column “G” as for game played. All other statistical info is recreational. If scores/stats are not inputted in this time frame players will lose that game in play-off qualifying.
3. Protests. All protests should be lodged to the “League” by Wednesday of the same week. All protests shall be decided by the “League”. The “League” will review with board members and/or advisory board members (Oversight committees). Send an email to admin@nimabl.com with details of the situation.
4. Season schedule should be released by early April pending field owners given availability with final revisions made by end of April. Holiday weekend are as follows.
5. Game Time. Umpires will officiate until a game is complete. Managers must mutually agree on start time and follow the rule. Typical game duration should be less than 3 hours in length. Time limits are as follows:
Exception: For fields that have a time limit, the game will be considered complete when time expires. Should the game not be completed, scoring will revert back to the last completed inning.
21's division exceptions
6. Ties are acceptable after official game designation and/or in the case of time-limit games. Weather shortened games and/or a daylight-shortened game scoring continues exactly where it was left off from. Scoring does not have to revert back to the last complete inning where one team had the lead over another. Official games must be official; 5 innings for 9 innings games and 4 innings for 7 innings games.
7. There will be a Slaughter Rule in regular season and postseason play.
8. Speed-up Rules - Pulling pitchers and catchers with two outs. Each team can individually decide when and where to use the speed-up rule of pulling a pitcher and/or catcher for a courtesy runner. In essence, every team has the right to pull the pitcher and catcher at two outs if they choose to. This does not affect the use of the allotted two (s) courtesy runners per game. (See Courtesy Runner Rules below)
9. Extra inning rule- With time reaming under Rule 5 game times, the following take place....
10. Courtesy Runners. A maximum two (2) courtesy runners per game are allowed NOT counting Pitcher/Catcher speed up rule. Courtesy runners can be named prior to, or during the game. Base running substitutions after using allotted courtesy runners must follow Major League Baseball rules.
Pitchers
1. No player while pitching may wear white or gray sleeves, nor may a pitcher wear a batting glove or wristband while pitching.
2. One intentional walk per game will be allowed. If a second intentional walk is attempted, a balk will immediately be called and all base runners will advance one base.
3. Pitchers are allowed three (3) hit batters. Upon hitting the 3rd batter, a pitcher must be removed from the pitching position for the duration of the game. A removed pitcher is allowed to play any other defensive position.
On the Bases
1. Decoy Rule. Any fielder may use a decoy only if it serves a strategic purpose. For example, if a fielder, who sees a man attempting to steal second base during a hit and run, looks upward into the sky and says that he’s got the pop-up when in fact the ball has been hit on ground is a legal decoy as it may cause the runner to retreat to first base and prevent him from advancing.
2. Sliding is not mandatory. A base runner who does not slide at a base or plate IS NOT automatically out; even if there is minor incidental contact that does not affect the outcome of the play.
3. A base runner who slides or stays up when advancing must go toward the bag, not toward the defensive player. A base runner who “takes out” a defensive player with a purposeful collision (e.g. Lowering shoulder, spikes high, body block) or a base runner who sets a screen will be automatically out; and is subject to immediate game ejection or warning; all at the discretion of the umpire.
4. Defensive players must allow the base runner a straight, clear path to reach the base. A defensive player is NOT allowed to position himself in the base path unless he has possession of the ball or the trajectory of the ball takes him there. If a defensive player blocks the base prior to fielding the ball thereby hindering the runner’s true course to the base, the runner will automatically be awarded the base. A defensive player CAN block a base if he actually has the ball. Warnings or ejections for repeated violations by a defensive player will be the umpire’s discretion.
5. Catchers. A catcher must field the ball behind or in front of the plate; or to the first base side of the plate. A catcher CANNOT set-up to field the ball on the plate or on the third-base line. If the trajectory of the ball takes him to these areas, this is okay. The catcher must bring the tag to the plate. A catcher CAN block the plate if he actually has the ball. Infractions will result in the runner automatically being awarded the plate. Warnings and/or ejection for (repeated) violations by the catcher will be at the umpire’s discretion.
Play-off Qualification, Game Credit, Standings Tie-Breakers
1a. 21s Division. A player needs eight (8) games played PLUS
1b. 35s Division. A player needs eight (8) games played PLUS
1c. 48s Division. A player needs six (6) games played PLUS
1d 58s Division. A player needs six (x) games played PLUS
A player must have xx MIN games played in the league and on the team, he is playing on in the play-offs. If a player played 4 games with a team in one division and 3 games with any NIMBL team (regardless of division) this does not qualify him to play for either team; he must have 8 or 6 games on the team he is playing on in the play-offs.
Exceptions. For players that missed game due to injury, MGR must have reported to league via link online. Games after that will be taken into consideration for playoff credit. 1 Gm = minus 1 Gm less and 1 PA or 1 IP or 1 In played in field (48s).
2. Game credit is given when:
3. If there is a tie in the Division standings at the end of the season, for whatever reason, the tie breakers will be as follows:
5. Playoff format
21s division
35s division
48s division
Player's Behavior and Team Responsibility
The “League” has the right to fine, suspend and/or expel any team member who abuses “League” rules or who does not exhibit a sense of sportsmanship; or any team member who plays without regard to the safety of the umpires or other players.
1. Managers and players shall display good sportsmanship at all times. No manager or player shall commit the following:
2. NI-MBL takes the stance that as adults you know there should be no beer or alcoholic beverages permitted at the field before, during or after the game. The field refers to the general playing area and ancillary areas. The “League” will only take appropriate and necessary steps when notified by a “FIELD OWNER” that drinking by a team member(s) has occurred. In addition, if the “League” is notified of an intoxicated player entering a game, appropriate and necessary steps may/will be taken by the “League”.
3. The “League” has the right to suspend or expel any team member who abuses “League” rules or who does not exhibit a sense of sportsmanship or who plays without regard to the safety of the umpires or other players.
4. Fighting among players or aggressive physical contact with an umpire will not be
tolerated. Players expelled from the game for either violation are subject to league suspension or expulsion.
5. NI-MBL WILL issue suspensions or expulsions infractions unbefitting to the image and policies of the “League”.
Ejections
An umpire or the League’s Commissioner has discretion to expel any player or manager from the game; during the game.
There is a “Three Strikes process” for ejections.
Appeal process.
One rep from each division (3) makes up the Rules committee and convenes and votes on suspensions to be upheld by Voting simple majority. Statements to be inquired upon to the player, MGRs present and Umpire statement.