I tried finding something on mlb.com, and emailed a question to the announcers for the Braves hoping they’d answer the question during the current Astros/Braves game, but no luck getting an answer to this.
Lets say the Braves and Astros were playing a doubleheader tonight. In game one, the Astros catcher suffers a serious injury, one that will obviously sideline him for weeks. Then, his back-up gets knocked cold on a collision at the plate. Boom, you’re down to your emergency C (in the case of the Astros, probably Craig Biggio) and blam - wouldnt ya know, he pulls a hammy at the end of the game.
Obviously, the Astros are calling up someone from AAA immediately, but that doesn’t help for Game 2 of the doubleheader. The QUESTION (finally): could the Astros sign their bullpen catcher, or I suppose some guy sitting in the stands who looks like he can catch, to a major league contract and use him that day?
If you wanted to add a player in between games of the doubleheader who was not on the 40-man roster, you’d have to sign the guy to a major league contract, take someone else off the 40-man roster (or move somebody to the 60-day DL) and hope you can get all this paperwork approved by the Commissioner’s Office before the next game starts.
I would add that pitchers are often brought up and down from the minors between games of doubleheaders. Teams will bring up a starter from the minors for Game 1 and then send him back down after the game is over and activate somebody else from the disabled list for the nightcap.
It would be significantly harder to do with a position player.
Given enough time, most GQ hypotheticals come true, and this one very nearly did this past week. Except that no double-header was involved, and the emergency player would have been the manager, not a bullpen catcher.
Three White Sox infielders suffered minor injuries during Tuesday night’s game against Oakland. With a day game in Oakland the next afternoon, and no possibility of recalling a player from an east coast farm club in time, the White Sox considered activating manager Ozzie Guillen, a long-time shortstop whose career ended in 2000.
“If someone needed to go on the DL, I was reaching for the major-league rulebook, seriously,” said General Manager Ken Williams. (By which he means the rules governing contracts and rosters, not the playing rules.) He found no bar to signing and activating Guillen for a day, although the 40-man roster constraint mentioned by BobT would no doubt have applied.
Apparently the only reason it didn’t happen is that none of the injuries were deemed serious enough to force a player onto the disabled list, which entails sitting out at least 15 days. The White Sox ended Wednesday’s game with a catcher at third base and an outfielder at shortstop.
Trivia: Something similar to what you describe has happened in other sports. Most notably, in ice hockey. In the 1928 Stanley Cup, the NY Rangers goalie was injured and had to leave the game. They had no backup. A pro goalie was in the stands and the Rangers tried to sign and use him, but their opponents, the Montreal Maroons, refused. The Rangers were forced to activate team manger Lester Patrick, who was 44 and hadn’t been a goalie in his playing career. Patrick allowed only one goal, and the Rangers won the game in overtime.