JUPITER, Fla. -- The first round of cuts in nearly any Spring Training camp carries few surprises. It's the catchers who were merely there as extra bodies to catch all the pitchers, and the low-Minors prospects who weren't going to make the team this year, anyway.

The second round, however, carries some stress for players on the bubble. Those who survive it can begin to dream, just a little.

Still, the dreams carry different doses of reality, even now. There are players who are still here because roles need to be filled in Spring Training games, and there are players who are still here because they seriously have a shot to break camp. Two weeks ago, it seemed that Matt Carpenter was more likely to be in the first group. But with each passing day, he looks more like he's in the second.

Carpenter, 25, has been in professional baseball for a year-and-a-half. He was drafted as a fifth-year senior out of Texas Christian -- and even then, only in the 13th round. Players with that profile simply don't rocket through the system, but Carpenter has done just that. He played at three levels in three months after signing in 2009, and advanced to Double-A last year.

Now, he looks like an actual contender to be one of the reserve infielders on Opening Day. He's not on the roster yet -- far from it. But he's advanced a long way in four weeks.

"Guys get at-bats, and they get it for different reasons -- opportunity, [or because they have a] realistic chance," manager Tony La Russa said. "Carpenter has gone from a guy who we had never really seen to a guy that has been fun to watch doing a lot of things right. He's going to play in the big leagues. When, I don't know."

What must be determined in the next 2 1/2 weeks is, primarily, whether Carpenter is good enough to play in the big leagues now. Secondarily, it's whether he fits within the roster the Cardinals are assembling. The club could decide it wants an experienced shortstop like Ramon Vazquez. Daniel Descalso's versatility could give him an edge. And, of course, Carpenter could fade once he starts seeing more Major League pitchers.

He's in the mix, though. As is so often the case in stories like this, it took an injury for Carpenter even to get the chance he's gotten so far. When camp started, Nick Punto had one backup-infield spot, and it appeared that the other would come down to Tyler Greene, Descalso and, perhaps, Vazquez. When Punto required surgery for a sports hernia, opportunity arose.

Carpenter seized it. He's 12-for-28 (.429) in 12 games -- not just producing, but showing a poised, mature approach at the plate. He's an opposite-field hitter who hasn't changed his approach -- whether he's batted second in front of Albert Pujols, third in Pujols' stead or lower in the order.

On Saturday, Carpenter got a start in the two-hole against Minnesota's Carl Pavano, definitely a prime-time opportunity for a young player at this point in camp. He struck out with a runner on second in the first inning, but singled three frames later. He's trying to keep the same mentality, regardless of the situation.

"All that is really out of my control," he said. "All I can control is when I get an opportunity to play, giving it my best effort and having good at-bats. Try to play good baseball. That's kind of how I've been going at it. When I got invited here, I was just excited to be a part of it. I got the opportunity to play, and I was trying to make the most of it. Things have kind of been going well for me, and I'm just trying to continue that."

Carpenter acknowledges that even he didn't expect to get this kind of chance when camp began. He's in a competition now, with players like Descalso and Vazquez. Greene looks likely to make the team, because the Cardinals need a backup shortstop. But the sixth infielder, and the backup for David Freese at third, could be Carpenter.

Freese's situation may be Carpenter's greatest help. The Cardinals expect Freese to play only about two-thirds of their games, as he recovers from surgery on both ankles. That means someone needs to be on the roster who projects as Freese's partner at third. If Carpenter is good enough, he might just be a great fit -- the left-handed hitter is even a potential platoon partner for the right-handed-hitting Freese.

"[He's getting] a lot of at-bats and playing time now," La Russa said. "It could go away. We could decide he's not ready or it just doesn't fit. He may be ready, but it doesn't fit our club. But the difference here is that Punto is out, so there are not only Spring Training at-bats, but there's a month of a spot for somebody. So we want to be inclusive, not just decide ahead of time."

It's not a guarantee, but it's a long way from where Carpenter was a month ago.