BRADENTON, Fla. -- Astros manager Brad Mills said on Tuesday that several of the team's position battles were beginning to come into focus, but the club is in no rush to begin finalizing its 25-man roster with more than a week remaining in Spring Training.

It goes without saying that non-roster outfielder Cory Sullivan has put himself in strong position to win the final outfield spot, based more on what he brings to the table than the numbers he's put up this spring. Sullivan is hitting .243 in a team-high 37 at-bats this spring and is vying for the fifth outfield spot with Jason Bourgeois, who's day-to-day with a strained hamstring.

Sullivan, 30, is a veteran of 419 Major League games and started in center field for the Rockies in 2006. Considering he can play all three positions, has experience and is a left-handed hitter, he appears to have a leg up on the speedster Bourgeois. Sullivan can also handle the bat, having tied a Major League record in '06 by putting down four sacrifice bunts in a game.

"Cory's done a nice job," Astros general manager Ed Wade said. "He's done exactly what we thought he was capable of doing when we signed him. He's a multiple-position, left-handed-hitting outfielder, and that profiles very well for us. We're not at the point of anointing anybody right now, but Cory's put his best foot forward and that's exactly what we knew he was capable of doing."

The Astros have six outfielders remaining in camp, with Carlos Lee, Michael Bourn and Hunter Pence set as the starters. Veteran Jason Michaels, who went 2-for-3 on Wednesday and is hitting .310 this spring, has the fourth outfield spot locked up, with Bourgeois and Sullivan competing for the final spot. Bourgeois has speed to burn, but he's dealing with his second hamstring injury of the spring.

"You try and find the situation that's best for you," said Sullivan, who hit .250 in 136 at-bats last season with the Mets. "There were a couple of other organizations out there that had similar opportunities, but the history of the Astros' organization and the opportunity itself, I thought it was the best one."

Sullivan, a career .276 hitter with the Rockies (2005-08) and Mets ('09), had to follow the path of many free agents in waiting this winter for an opportunity to get a contract. He signed with Houston on Jan. 20, with nothing guaranteed but plenty of playing time in the spring and long bus trips.

Still, with the Astros' starting outfield set and Michaels seemingly a lock, Sullivan thought he had a good chance to win a spot in Houston.

"There's always competition, but I try and use [the] spring to get ready for April 5," he said. "I know my skill set and they know my skill set. They've seen me do it before, but the idea is not to peak in April. You want to build through Spring Training and be ready April 5, and that's kind of how I approach it."

Sullivan was selected in the seventh round by the Rockies in the 2001 First-Year Player Draft and made Colorado's Opening Day roster in '05. He hit .294 with four homers, 30 RBIs and 12 stolen bases in 139 games that season and was the Rockies' starting center fielder in '06, hitting .267 with 10 triples, 30 RBIs and 10 steals in 126 games.

"I had a good '05 season, my rookie season, and in '06, they gave me the starting position and I had a typical sophomore season and struck out a lot [100 times in 386 at-bats]," Sullivan said. "Since then, I've made adjustments to get back to where I was in '05. Sometimes when you [struggle] that one season, though, you get phased out of the role. This is my job now, to play all the positions and I'm comfortable with that."

In his role as a bench player, being prepared when playing time arises is the key.

"I'm a pretty knowledgeable baseball player," he said. "I tend to be as prepared as I can knowing the game and what I have to bring each day: if it's coming off the bench or a pinch-hit at-bat, coming in late in a defensive situation or going out there to play the best defense I can. I can steal a base here or there and have a pretty good arm."

Sullivan, who played in three World Series games for the Rockies in 2007 and went 1-for-3, is one of a handful of Astros players in camp who have played in the Fall Classic, including Lance Berkman, Roy Oswalt, Brett Myers, Kazuo Matsui, Geoff Blum and Pedro Feliz.

Knowing what it takes to win, he looks around the Astros' clubhouse and believes it's a team that can be in contention in the National League Central.

"Absolutely," he said. "We just have to stay healthy. We're running into some of that problem right now, but hopefully by Opening Day, we'll be ready to go. After that, you've got your horses on the mound and guys that can put up runs. And we play solid defense. That's what the team [Rockies] was able to do in '07, and we'll be right there at the end."