KISSIMMEE, Fla. -- The battle to win the final spot in the Astros' rotation became clearer Sunday afternoon when left-hander Ryan Rowland-Smith was informed before the game against the Pirates he was now competing for a bullpen spot.

Rowland-Smith, signed by the Astros in December, started the 3-1 loss to the Pirates at Osceola County Stadium and pitched only two innings before turning the ball over to top prospect Jordan Lyles, who was dazzling once again in holding Pittsburgh to two hits and one run in 3 2/3 innings.

Lyles and veteran Nelson Figueroa, who held the Braves to six hits and one earned run in five innings in a split-squad game Sunday in Lake Buena Vista, appear to be the front-runners for the final rotation spot. The other two candidates -- Rule 5 Draft picks Aneury Rodriguez and Lance Pendleton -- haven't been getting many innings in the last week.

"I think things are beginning to become clarified at this point," Houston general manager Ed Wade said. "I think certainly before we break camp, if not sooner, we'll lend some more clarity to it."

Rowland-Smith, who has started 35 games for the Mariners over the past two years, now finds himself competing for a 'pen role with fellow lefties Fernando Abad and Gustavo Chacin. Rowland-Smith has appeared in 47 career games as a starter, going 9-16 with a 4.87 ERA, and 68 as a reliever, going 3-1 with a 3.68 ERA.

"I want to have a good last week and embrace whatever role they give me and contribute," Rowland-Smith said. "I've probably spent 50 percent of my career in the bullpen, and I've had a lot of success in the bullpen before I got a chance to start. Like I said, wherever I pitch, I want to be a part of this. I know I can contribute in different ways."

Figueroa came into camp as perhaps the top candidate for the fifth spot after going 5-3 with a 3.22 ERA in 18 games (10 starts) for the Astros last year. He induced an inning-ending double play ball in the fifth inning Sunday, but Jonathan Villar dropped a throw from Brett Wallace, allowing two unearned runs to score. Figueroa has a 3.86 ERA in four spring starts.

"I think if you take out that inning and a half over there against the Phillies [on Monday], I think I put myself at the top of the list, hopefully, for the No. 5 starter job," he said. "I definitely showed all the different things I could do -- a continuation of last year -- getting out there and pitching, keeping the team in the ballgame. They've been all close games for us. The bottom line is I think I can help this team out in that role all year long."

But don't count out Lyles, who was as sharp Sunday as he's been all spring. He struck out four and showed tremendous command of his fastball and his breaking pitches. Catcher Humberto Quintero, who caught him for the first time, was wowed.

"The ball moves a lot and he throws everything for strikes no matter the situation," Quintero said. "I'm excited when I see a young pitcher like this throw that kind of stuff. I'm surprised and excited because I've never seen a 20-year-old throw fastballs and breaking balls like that."

Lyles went a combined 7-12 with a 3.57 ERA in 21 games last year at Double-A Corpus Christi and Triple-A Round Rock, where he started only six games. In five outings this spring, including one start, he's allowed 11 hits, two walks and three earned runs in 13 2/3 innings for a 1.98 ERA.

"I made some good pitches, but I felt like I left some balls up that I usually don't as much as I did today," said Lyles, who isn't on the 40-man roster. "My cutter was good today. Q liked it and called it, and I mixed it in a little bit, making a variety of the size of it to lefties and stuff. If I wanted to go out and get a strikeout, I made it a little bit bigger. But overall I feel like my stuff was alright today."

Manager Brad Mills said Lyles will get another start, but more decisions have to be made before his plan can be mapped out.

"We've got a lot of things we're going to sort out the next couple of days," Mills said. "We're getting down to the last 10 days of Spring Training, and there's a lot of things we have to sort out."

Lyles said he hasn't been told what the future holds.

"I'm just getting ready for the season," he said. "I'm still trying to get my arm in shape. I'm going out there and hopefully I can build on the season I had last year. I felt pretty good right now, like I did going into last season. I'm going to continue doing what I'm doing and see where it goes."

Rodriguez, whom the Astros nabbed from the Rays in the Rule 5 Draft, threw a scoreless inning Sunday against the Braves and walked two. He has pitched more than two innings in a spring game just once, a signal he's probably not in the rotation hunt.

Pendleton, a Houston native drafted from the Yankees, has pitched three combined innings in the past nine days. The Astros would have to offer both Pendleton and Rodriguez back to their former teams if they don't make the 25-man roster.

"The two Rule 5 guys have done a nice job," Wade said. "In their circumstances, even if we come to a determination that somebody else has stepped into the fifth spot, we'll probably hold onto them as long as we can. Even if they don't make the club, we'd love to keep them in the organization, but those are conversations we would have to have with the Yankees and the Rays."

With about a week before the Astros leave Florida, Wade has been pleased with how all the rotation candidates tackled their jobs this spring.

"It's been fun to watch," he said. "Even beyond that group, we think there are some others that if we had to slide them into starting roles, they would be able to step up and fill a spot in the rotation. We're pleased with the depth we have right now. We're not out looking for pitching at the moment."