"Umpires and/or replay officials must consider whether the fielder had secured possession of the ball but dropped it during the act of the catch. An example of a catch that would not count is if a fielder loses possession of the ball during the transfer before the ball was secured by his throwing hand."
This was the first time this season that the Cardinals have seen a play in which there seemed to be grey area as to how the rule would be applied. In this instance, Nationals second baseman Danny Espinosa caught a feed from his shortstop, but then dropped the ball as he went to grab it from his glove.
"It looked like one of those plays where you'd typically see an out called in the past," Matheny said.
Jon Jay appeared to think so, too, as he was beginning to come off the base and head to the dugout when he saw the umpire signal him safe.
"What's going to have to happen is we're going to have to adhere to what the rule originally said," Matheny said. "My interpretation is that it has to be in the act of throwing. If the arm is going forward and the ball is lost, that is different than if the catch is made and then the transfer is made before the arm actually moves into the throwing process. Now, what exactly that looks like, I'm not sure."
Nationals manager Matt Williams came out to argue the call, but chose not to challenge. He told reporters afterward that his video staff in the clubhouse concluded that "it didn't look like he had a whole lot of control."
Matheny, who has not used a challenge yet this year, said he will likely be aggressive in challenging this sort of call until there is a better understanding of how the rule will be consistently applied
"Will it blow up in our face? I don't know because it just seems kind of loose at this point," Matheny said. "It definitely looks different. I believe it's probably just one of those issues that's going to be worked out over time. I think the longer we're involved in this replay process, the more we're going to understand how things will be ruled.
"I'm sure if that happened against us, I would have been out there making some sort of fuss. It's one of those holes, I think, because it's just been done differently. I think it's going to be a change in the game. I think it will take a little time, but it will be interesting to see how it plays out."
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.