The Blue Jays had an unexpected wrench thrown into their bullpen plans in Thursday's 4-3 walk-off loss in Atlanta when Jacob Waguespack came out to warm up for the sixth inning.

Waguespack was ruled ineligible by home-plate umpire Alan Porter because his name was left off the lineup card, and he could not pitch. After the game, Blue Jays manager Charlie Montoyo said that Waguespack was included on the updated lineup cards that the Blue Jays had in their dugout, but those updated cards were not the same as those that the umpires had on the field.

"What happened was MLB didn't get that to the umpires. It was in all of our cards and I don't get to see that anymore. There's no exchange of lineups anymore. It's digital, so it goes straight to the umpires. For some reason, the ones they had, he wasn't on it.

"Our bench coach [Dave Hudgens] does it. He sends it to the umpires, and it goes digital. They tell you, 'Any changes?' And no, there's no changes, because we already sent it in. I guess [Waguespack] wasn't on their card. ... The one [Porter] has is the one that counts."

Earlier Thursday, Waguespack had been optioned to the club’s taxi squad along with Santiago Espinal as the Blue Jays cut their roster down to 28 players. Soon after, though, Waguespack was added back to the active roster when the Blue Jays placed right-hander Trent Thornton on the 10-day injured list.

With the Blue Jays trailing, 3-1, in the top of the sixth, Waguespack came out to begin his warmups when Porter looked over his lineup cards and spoke with third-base umpire Marty Foster. The two then went to the Blue Jays’ dugout for a conversation with Montoyo before Waguespack, clearly frustrated, was forced to leave the mound.

Montoyo wasn’t aware of the issue until then, as Waguespack was walking to the dugout.

“When he came in, the umpire said, ‘He’s not on our card,’” Montoyo explained.

Braves manager Brian Snitker offered his thoughts from the other dugout, focusing both on the additional substitution for reliever Rafael Dolis -- including the time required -- and how the delay impacted his own starter, Touki Toussaint, who was in the midst of throwing a career-high nine strikeouts.

“He wasn't on the card, the guy they brought in,” Snitker said. “They evidently made two cards. The timestamps were the same because he was on our card, the one we had in the dugout. I don't know how all of that works. I don't like that though. I think that needs to be looked at. I understand. I don't want a kid [Dolis] to get hurt because of some clerical error. But there's something that has to be done because that's not fair to Touki to leave him in the dugout for an extended period because of a clerical error."

Over three appearances this season, Waguespack has tossed four scoreless innings with four strikeouts.

MLB’s Official Baseball Rules, 4.03(c), addresses “Exchange of Lineup Cards” and substitutes as such:

“As a courtesy, each lineup card presented to the umpire-in-chief should list the fielding positions to be played by each player in the batting order. If a designated hitter is to be used, the lineup card shall designate which hitter is to be the designated hitter. See Rule 5.11(a). As a courtesy, potential substitute players should also be listed, but the failure to list a potential substitute player shall not make such potential substitute player ineligible to enter the game.”