Astros manager Bo Porter replaced relief pitcher Paul Clemens with left-handed reliever Wesley Wright. This prompted Mike Scioscia to call for a right-handed pinch hitter. Porter then went back out to the mound to call for right-handed pitcher Hector Ambriz. The homeplate umpire as Porter was making the change went out to talk to Porter. After a brief discussion Porter was allowed to bring in Ambriz. This lead to Scioscia coming out to dispute the pitching change.
Several times Scioscia attempts to explain to the umpires the Wright has to face at least one hitter. The umpires huddled again to talk about allowing Porter his pitching change and apparently made the determination that Porter was allowed to make the change. Scioscia then indicated that he would be protesting the game.
According to rule 3.05b:
(b) If the pitcher is replaced, the substitute pitcher shall pitch to the batter then at bat, or any substitute batter, until such batter is put out or reaches first base, or until the offensive team is put out, unless the substitute pitcher sustains injury or illness which, in the umpire-in-chief's judgment, incapacitates him for further play as a pitcher.
Unless Wright is injured he must face at least one hitter as Scioscia indicated; however, the Astros may have an out with rule 3.05c:
(c) If an improper substitution is made for the pitcher, the umpire shall direct the proper pitcher to return to the game until the provisions of this rule are fulfilled. If the improper pitcher is permitted to pitch, any play that results is legal. The improper pitcher becomes the proper pitcher as soon as he makes his first pitch to the batter, or as soon as any runner is put out.
Rule 3.05(c) Comment: If a manager attempts to remove a pitcher in violation of Rule 3.05(c) the umpire shall notify the manager of the offending club that it cannot be done. If, by chance, the umpire-in-chief has, through oversight, announced the incoming improper pitcher, he should still correct the situation before the improper pitcher pitches. Once the improper pitcher delivers a pitch he becomes the proper pitcher.
It appears that if the umpires goof the rule then the Astros won't suffer from the protest. If the Angels lose Thursdays game and they win the protest then the Angels and Astros will have to replay the game from the point of the game in which the protest was issued.
The other out is for Wright to be injured but that appears unlikely as he threw several warm up tosses without any sort of indication he was injured and there was no trainer visit to the mound when Porter made the switch. Post game comments should be interesting to say the least.
Update: The protest becomes null due to the Angels winning the game.