The trade wasn't one Mozeliak entered into lightly.
"These decisions are never easy to make," Mozeliak said at the time.
If Mozeliak hasn't seen the upside of that deal -- a three-team trade with the Jays and White Sox that involved 11 players -- by now, he certainly did Wednesday.
Three of the four players the Cards netted in that July 27 deal contributed heavily to a 5-3 victory over the Phillies in Game 4 in the National League Division Series, helping to ensure that there will be a Game 5 on Friday in Philadelphia.
"They've been great," St. Louis outfielder Jon Jay said. "All of them have done a really good job of contributing. You look at our roster, and we've had different guys stepping up at different times. Those guys have been a big part of that."
On Wednesday, starting pitcher Edwin Jackson, obtained from the White Sox, allowed two runs on five hits in six innings for the victory. Jackson yielded both runs in the first inning, but settled down thereafter.
Reliever Octavio Dotel, who came over from Toronto, got the final two outs of the seventh inning. Finally, another reliever, Marc Rzepczynski, who was also with the Blue Jays, got a big out in the eighth inning, striking out Ryan Howard to end the frame after Philadelphia had already scored to cut the lead to 5-3.
"It really helped our bullpen, especially since [manager Tony La Russa] had roles for all of them," Cardinals left fielder Matt Holliday said of the trade. "It gave us a much better setup for the seventh, eighth and ninth innings.
"I'd say their contributions really picked us up."
That was evident in Game 4, as La Russa leaned heavily on three players who weren't a part of his Opening Day roster. Heck, these guys weren't even around until the last few days of July, arriving just in time to help trigger a late-season playoff push.
"The gentleman that made the trade was John Mozeliak. He's the guy, he talked to the coaches, the staff about what our needs were, then he talked to the scouts," La Russa said. "He pieced it all together."
While the Cards were criticized after the deal for giving up on a player like Rasmus, there's no arguing now that the move was the right one.
And for players like Jackson, who went from a non-contending team to one on the cusp of making a run to the postseason, the trade has been something of a professional rebirth.
"It's been a blast. We brought a lot of energy over with us, pretty much every guy that they brought over has a lot of energy, and maybe that's what this team felt like they needed," Jackson said. "We just jelled in with what they already have, and everybody has been working out together perfect.
"It's been like the missing pieces to the puzzle, and we've all been having a lot of fun, and that's how we are where we are today."