BRADENTON, Fla. -- When incumbent starter Jason Castro went down, likely for the season, with a torn anterior cruciate ligament, that gave an opportunity for J.R. Towles or Carlos Corporan to seize a roster spot that wasn't there when Spring Training started.

Unless the Astros pick up another catcher in the final week before the start of the regular season, it appears they will begin the season with Quintero and Towles alternating time behind the plate. Quintero will start Opening Day and catch Brett Myers, who flourished with Quintero behind the plate the second half of last year.

"Both of them have performed really well, and there's no reason to think they wouldn't be able to handle the situation moving forward on into the start of the season," said manager Brad Mills, who's not ready to announce any decision on which two catchers he will carry. "Corporan has also done a good job back there and has opened some eyes as well, which has been nice."

Towles, last year's Opening Day catcher, entered Wednesday hitting .314 with two homers and six RBIs, Quintero was batting .393 with five RBIs and Corporan was hitting .381. Mills said he's noticed a difference in the way Towles has carried himself this spring.

"I think the experience of going through that last year [trying to win a job in Spring Training] has definitely helped," he said. "It's more about the way he carries himself and how he interacts with the pitchers and how he interacts with the staff and his demeanor."

Options factoring into Astros' roster decisions

BRADENTON, Fla. -- As the Astros debate their remaining roster decisions in the next few days, one of the factors that will come into play is which players are out of options. Players who are out of options and don't make the 25-man roster must clear waivers before being sent to the Minor Leagues, so the Astros would risk losing them.

The Astros have seven players who are out of options for 2011 -- right-handers Nelson Figueroa and Alberto Arias, infielders Clint Barmes, Angel Sanchez and Jeff Keppinger, catcher Humberto Quintero and left-hander Ryan Rowland-Smith. Of those, only Sanchez and Rowland-Smith are battling for roster spots at this point.

"It's certainly something we talk about," general manager Ed Wade said. "We try to weigh all factors, including out-of-options status. Whether it's one of the out-of-options guys or the Rule 5 players, we try to factor in everything before we make a decision."

Sanchez, who returned to the lineup Wednesday after missing a few days with an upper back strain, is among five players competing for two backup spots on the infield. Rowland-Smith is in the hunt for a slot in the bullpen. Keppinger will start the year on the disabled list, and Arias is likely to as well. Barmes, Figueroa and Quintero are locks to make the club.

Pitchers Lance Pendleton and Aneury Rodriguez were both taken in the Rule 5 Draft, which means they must remain on the 25-man roster all season or be offered back to their former clubs. That's assuming the Astros can't work out a trade to keep them. Pendleton came from the Yankees, and Rodriguez from the Rays.

Slide gets Pence four stitches on shin

BRADENTON, Fla. -- Astros right fielder Hunter Pence needed four stitches to close a gash on his right shin Wednesday, an injury that occurred while he was sliding into home plate in the fifth inning of a 10-6 win over the Pirates at McKechnie Field.

"I'm totally fine," Pence said. "I'll be ready to play [Thursday]."

Pence, who went 3-for-3 with his first spring homer, two runs scored and two RBIs, wasn't exactly sure what caused the cut. He slid home while scoring from second base on a double off the bat of Jason Michaels.

"It all happened so fast," he said. "I didn't know I was cut until I took my sock off. I thought I was just going to ice it for a little bruise. It was cut. They just wanted to put a few stitches just so it's precautionary and there's no infection."

Astros manager Brad Mills wanted Pence to play seven innings Wednesday and said the team's 2010 Most Valuable Player will be reevaluated Thursday morning.

"No reason to rush him back," he said. "He's going to get plenty of at-bats."

Quintero shows off arm, bat

BRADENTON, Fla. -- It's no secret catcher Humberto Quintero likes to show off his arm. At least, it shouldn't be by now. Quintero led all Major League catchers last year by picking off seven baserunners, doing it in a backup role.

But somehow Pirates catcher Ryan Doumit managed to get picked off twice Wednesday by Quintero, who cut him down while he wandered off second base in the fourth inning and again at first base in the sixth. Quintero also went 3-for-3 to raise his spring average to .452.

"I think everybody in the National League knows that I'm going to throw," Quintero said. "I'm not scared to throw and I'm going to help my pitchers. If they go off the base, I'm going to try to throw them out. It's good for us."

Last Aug. 23, Quintero picked off Philadelphia's Jayson Werth at second base to end the sixth-inning of the Astros' 3-2 win over the Phillies at Citizens Bank Park -- a four-game series Houston swept. The throw was replayed countless times on highlight shows.

"That's such a weapon to have his arm back there," manager Brad Mills said. "It's a strong, accurate arm, and he showed it back there today. It's absolutely outstanding. ... It really gives the ballclub a lift and the pitcher a lift because it got an out he wasn't thinking he might get."

Worth noting

Aneury Rodriguez, Ryan Rowland-Smith, Brandon Lyon and Lance Pendleton pitched in Minor League games on Wednesday. Lyon retired all six batters he faced, striking out two; Rodriguez retired all nine batters he faced, with one strikeout; Rowland-Smith gave up two hits, one walk and one earned run in two innings; and Pendleton allowed six hits and three earned runs in two innings. ... Infielder Angel Sanchez made his return to the lineup Wednesday after missing a few days with a strained back. He went 1-for-2 with a run scored and a walk. "I'm feeling perfect, feeling good," he said. "I'm just ready to go and be back on track."