A cynic would say because it's not normal to start facing hitters after throwing only one mound session in the bullpen. But as manager Mike Matheny noted earlier this week, Carpenter isn't all that typical.
And so he continues his process back from thoracic outlet surgery with his eye on pitching before the season ends. That's the basis for the aggressiveness. But Carpenter also sees no reason to hold back since he feels so good.
"Like I've said all along, I'm not just going to sit around and waste a month and just throw bullpen [sessions]," Carpenter said. "If I have a shot [at pitching this year], why not push it? Today was that step, and I felt good.
"It's still my second session, and we need to continue to take it like that. If I wake up tomorrow and I feel good, I'll be excited and we'll do [this again] at some point in time at the beginning of the week."
Carpenter estimated that he threw about 36 pitches -- a mixture of fastballs and offspeed ones -- to various position players who stepped in to help the right-hander simulate an at-bat.
This was the first time Carpenter had thrown batting practice since June 22. His arm did not respond well after that session, which prompted a visit to Dr. Gregory Pearl. That eventually led to surgery that, at the time, was deemed season-ending.
That's why the next few days will be telling.
"The ball is jumping out of his hand," Matheny said. "Having him take a step forward is a big deal that all of us want to be a part of. Whenever things are starting to move forward, that just amps him up and increases his presence in this clubhouse and on the bench."
That said, neither the Cardinals, nor Carpenter, are making too big a deal of these steps forward. There have already been several instances this year when Carpenter thought he was on his way back toward game action and then endured a setback.
"I'm not going to get too excited," Carpenter said. "I'm not going to get too crazy. I'll hopefully recover well the next few days and do this again early next week and go from there. At some point in time, we know we're going to get to a point where we know we're going to have to make a decision to push it to that next level or not."