CLEARWATER, Fla. -- It is no secret that one of the most intriguing roster battles at Phillies camp is at catcher.
Jorge Alfaro is a lock to make the team because he is out of options, leaving Cameron Rupp and Andrew Knapp to compete for the No. 2 job. Both have an option remaining, so either could open the season in Triple-A Lehigh Valley.
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"I'm coming in to compete for a job and prove myself," Rupp said at Bright House Field. "I'm going to do everything I can to prove myself that I belong there. There are definitely things I can work on, but overall the power output was there. I threw guys out. Defensively, I got better as the year went on."
So what are the Phillies looking for in their catchers? Manager Gabe Kapler said Thursday afternoon that the "meat and potatoes" for a catcher is framing pitches, blocking balls, throwing out runners, game planning, etc. He said catchers also must develop strong relationships with their pitchers.
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"How much confidence can they inspire in our pitchers?" Kapler said.
Kapler initially did not mention offense, although offensive performance will be critical, as no Phillies catcher has an advantage over the others defensively.
"We value controlling the strike zone," Kapler said. "We value the ability to drive the ball out of the ballpark. Interestingly, all three catchers have that capability. They have it in them."

Knapp posted a .368 on-base percentage last season as a rookie, and Rupp's career mark is .298. But Rupp has power. He has hit 30 home runs over the past two years.
"Knapp has done a really good job of controlling the strike zone," Kapler said. "He works a deep count, real professional at-bat -- and those are things we value. That's not to say we don't value other things on the offensive side, but those are some things that we think about."
"We're going to expose these guys to a lot of different situations, ask them to do a lot of different things and we'll make the best decision for this club," Phillies general manager Matt Klentak said. "You've heard me for two-plus years now talk about the importance of depth, not at any one position, but at every spot on the roster. And for us to have three quality Major League catchers puts us in a position that I dare say is as good as most teams in the league."
Eight is enough
Klentak said the Phillies still plan to carry an eight-man bullpen.
"I can't promise we'll have it for 162 games, but I would think for the majority of the year we will try to do that," he said. "If we do not add a marquee starter, we feel like there are a lot of ways for us to improve our run prevention, but specifically our starting pitching even if we don't change the personnel in the rotation.
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"One of those ways is by addressing the bullpen. We carry an eight-man bullpen with quality arms one through eight, and that is going to make the rotation better. We don't have to push a starter into whatever it is, the sixth or the seventh inning, and push them beyond their comfort level where they are vulnerable to a big inning because we have a top-notch bullpen to go to in those middle innings."

Extra bases
• Kapler sees big things from Aaron Nola. "This is a guy that carries himself like a superstar," he said. "A very quiet superstar, but one that knows what he needs to do to prepare for the season."
• It is no surprise Carlos Santana's locker is next to Maikel Franco. The Dominicans have spoken regularly in the offseason. The Phillies are hoping some of Santana's plate discipline rubs off on Franco.
"It's definitely not by accident," Kapler said of Santana and Franco being neighbors in the clubhouse.
• Kapler saw some early pop from J.P. Crawford in batting practice. "I think he will hit for more power," he said.