KISSIMMEE, Fla. -- Astros manager Brad Mills admitted Sunday he's concerned about the back condition of infielder Angel Sanchez, who's trying to make the club in a reserve role. Sanchez only has 28 at-bats and is hitting .250.

Sanchez has been limited since straining his upper back swinging the bat last week. He took ground balls Saturday and was hoping to be able to swing a bat Sunday, but Mills didn't expect him to play in a game until Wednesday.

"We want to make sure we can get his back straightened out and get going," Mills said. "Right now, I don't have him playing until Wednesday I know he'd like to play before that, but I want to make sure he's 100 percent so we don't have any regress with that.

"It might not be a concern to him right now, but it's a little bit of a concern to me because he had it when he started Spring Training, although it's starting to act up, although it is in a different spot and a different kind of soreness."

Sanchez got the lion's share of playing time at shortstop when Tommy Manzella got injured in the middle of last season. He responded by hitting .280 with 25 RBIs in 250 at-bats.

"He's done a real good job defensively for us," Mills said. "He was solid last year, so that's not a big surprise. He's able to give you a good at-bat all the time, which is really crucial."

Hot spring has Wallace in good position

KISSIMMEE, Fla. -- The Astros aren't prepared to name Brett Wallace as their starting first baseman -- and there's nothing stopping them from waiting until his name is penciled into the lineup Opening Day in Philadelphia -- but it appears more and more likely that will happen.

Wallace, 24, went 2-for-3 with a run scored in Sunday's split-squad game against the Braves to raise his average to .380. He has 14 RBIs in 50 at-bats after driving in 13 runs in 144 at-bats in his Major League debut last year after being traded to Houston.

"I think Brett's had an outstanding spring and has done everything we hoped he would do coming in," general manager Ed Wade said. "I don't know that we necessarily have to announce our first baseman more than we have to announce who the shortstop is going to be."

But there was some uncertainty surrounding Wallace, who struggled at the plate last year and wound up splitting time at first with Carlos Lee in September. The Astros were prepared to move Lee to first base if they didn't think Wallace was ready.

"We're moving towards that way of thinking, that he is going to be our first baseman even without saying that to him," manager Brad Mills said. "We still have 10, 11 days left. Let's let him continue to have a good spring and let us morph into that. It's heading that way. It's no big secret to anyone. It's moving that direction. It's fair to say that."

Wade has been pleased with how Wallace has played in all facets this spring.

"Brett's had a really good spring," he said. "His bat stays in the hitting zone for a long time, he sees the whole field, he's had a good two-strike approach down here and played excellent defense and throws well. He's agile and runs the bases well. I think he's come down here and recognized the things he has control over and has handled them all exceptionally well."

Ex-Astros great Cedeno back in uniform

KISSIMMEE, Fla. -- Cesar Cedeno, who starred with the Astros from 1970-81, has been hired by the club as a Minor League instructor. Cedeno coached first base against the Pirates on Sunday and will be in uniform during extended Spring Training and in the Gulf Coast League.

"We think he's got the experience to relate well with the kids," general manager Ed Wade said. "We've got a lot of good feedback from the time he spent in other organizations as a coach. We saw him early in the spring and knew he didn't have anything going on at that point in time and began to talk about it internally and decided to bring him in."

Cedeno, 60, made four All-Star teams and won five Gold Gloves in the outfield with Houston and was named the team's Most Valuable Player in 1972. He still ranks first on the club's all-time list in stolen bases, fourth in at-bats and hits, sixth in games played and runs scored and fifth in total bases.

Wade said Cedeno will also assist roving outfield/baserunning instructor Milt Thompson. Cedeno had previously worked in the Nationals' organization.

"He was a tremendous player and certainly a cornerstone for the Astros for a long time," Wade said.

Wright making transition to sidearmer

KISSIMMEE, Fla. -- Left-hander Wesley Wright has been working closely with Astros pitching coach Brad Arnsberg in the last week to lower his arm slot and make the transition into a sidearm pitcher.

Wright, who had given up eight earned runs in six innings this spring before Sunday, has tinkered with the new arm slot in one Grapefruit League game and will continue to work closely with Arnsberg to complete the transition.

"The results haven't been great the last couple of seasons for Wesley," general manager Ed Wade said. "There was internal discussion, even during the winter, of the possibility of dropping him down. Wes and Arnie got together probably 10 days ago and talked about it, and in one of his relief appearances he dabbled in it and threw a few good pitches.

"He got hit around overall and came out of it, and he and Arnie got together again and decided to make the full commitment to it. Arnie's very excited about the potential that Wesley shows at the lower arm angle. He's got good sink, and it's certainly something that if Wesley is comfortable throwing then we think he's got a chance to be very successful."

Wright, taken by the Astros in the Rule 5 Draft in 2007, has a 8-9 record with a 5.33 ERA in 134 career games.

"Wesley is a very intelligent guy and he's got good stuff," Wade said. "He's been hit around the last couple of years, and Arnie particularly is a big proponent of him doing this because we think with the stuff that he's got he can be very, very effective from the lower arm slot."

Worth noting

Left-hander Wandy Rodriguez, who was scratched from his start this past Tuesday because of mild tendinitis in his right shoulder, threw in the bullpen Sunday without any problems and will start Tuesday against Washington in Viera, Fla. ... Pitcher Jordan Lyles had a sacrifice bunt and a single in his two plate appearances Sunday. His single went off the wall, and Lyles thought it was a home run after first-base coach Cesar Cedeno told him, 'Good job.' Lyles got caught in a rundown that ended with Humberto Quintero being tagged out. "I kind of dropped my head, which I shouldn't have done," Lyles said. "It's something I can look back on and laugh at. I thought I had it."