But what, exactly, might the Cards buy?
"It's certainly one of the more difficult teams to evaluate in terms of, 'Where is your quick fix?'" Mozeliak said on Monday. "I assure you, I spend many nights just trying to think about if you had that winning lottery ticket, where do you place it? And I don't know the answer to that.
"It's more of an exercise of, 'Well, who might be available? And what does that look like on the club?' Then obviously I ask myself what's the cost of that acquisition and who are they going to be asking for?"
The Cardinals don't have any glaring holes created by injury. The rotation, after underachieving early this season, has settled. And the offense has been one of the league's most productive. The club is already oversaturated with infielders, and the hole in center field has been plugged by Tommy Pham and Kolten Wong. Randal Grichuk has positioned himself as an option to return soon, too.
The most vulnerable area of the Cardinals' roster right now appears to be the bullpen, which is without Kevin Siegrist (mononucleosis) and in flux after Trevor Rosenthal's removal from the closer's spot. Many of Mozeliak's recent Trade Deadline moves have been to bolster the bullpen, and it wouldn't be surprising if this year he does the same.
But he also isn't ready to limit his pursuits there.
"I haven't been knee deep in the reliever market," Mozeliak said. "If you think about just the last week and a half, our bullpen seemed pretty good. But over the next 25 days or so, we will definitely have to engage in all markets. We can't ignore anything."
Mozeliak will also weigh what's available externally with the options he has ready in Triple-A. On the pitching side, top prospect Alex Reyes could still be a midseason addition, and Mozeliak cited Triple-A starter Mike Mayers as another player on the cusp of making a big league impact.
The Cardinals have not hesitated to promote Minor League starters to fill Major League bullpen spots in recent years. Rosenthal, Seth Maness and Carlos Martinez all made that jump under manager Mike Matheny with much success.
"Where [Reyes] slots in, he could absolutely be the most dynamic thing that happens to this club with the least acquisition cost," Mozeliak said. "I feel like there are some options for us internally where we just need to be patient and see how some of this slots as we go."
Jenifer Langosch has covered the Cardinals for MLB.com since 2012, and previously covered the Pirates from 2007-11. Read her blog, follow her on Twitter, like her Facebook page and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.