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06/12/11 7:58 PM ET

Mills watches video of Lyon's rough outing

HOUSTON -- Astros manager Brad Mills spent some time following Saturday's 6-3 loss watching video of Brandon Lyon's rough outing against the Braves. Lyon allowed four runs without recording an out in the 10th inning in his second appearance since being activated from the disabled list.

"The big thing that struck me last night was locating those pitches, and I think he would probably say the same thing," Mills said. "When the catcher is setting up away and the pitch winds up over [the plate], something's different. That's not him."

Lyon missed 32 games with right biceps tendinitis and a partial rotator cuff tear and returned to action Friday and gave up a home run in one inning.

"Maybe he's getting a feel for it," Mills said. "We're going to have to do what we can to find out why Brandon Lyon isn't throwing the ball like Brandon Lyon can."

Pence gets the day off, hit streak on hold

HOUSTON -- Astros right fielder Hunter Pence, who's riding a 22-game hitting streak, was out of the lineup for Sunday's game against the Braves, with Jason Michaels starting in right field. Pence has been dealing with lower back spasms.

Jason Bourgeois was originally going to get the start in right field, but he was scratched about an hour before the game with an ankle sprain and Michaels started in his place.

Astros manager Brad Mills said Pence and head athletic trainer Nate Lucero came into his office following Saturday's game and expressed concern over Pence's back condition.

"Hunter doesn't want to ask for a day off," Mills said. "God bless him. That's the way you want everybody to be. But throughout the conversation, he said it hurt him when he ran and felt like it was going to lock up on him. If it locks up on him when he tries to do something, it could really hurt something. With a day game following a night game, the chances of that happening go up. At the end of everything, we felt today would be a good day to take off."

The Astros are in a stretch of 16 consecutive games without a day off, and Pence has started every game in right field.

"It only makes sense for him to take today off," Mills said.

Pence, who's hitting .391 during the streak, told reporters Sunday morning his back feels fine.

"They told me last night they wanted -- with a day game after a night game -- they wanted to give me a day rest and come back ready to go," he said. "I felt good after the game, and that's that."

Mills said his goal is to try to not use Pence as a pinch-hitter, and not just because he has a 22-game hitting streak on the line.

"He needs today off," Mills said. "If some unforeseen thing happens with someone getting hurt, and he has to play and we got 15 innings and we have no one else, that's something we have to weigh at that time."

Lyles staying in rotation; Fulchino sent down

HOUSTON -- Jordan Lyles will remain in the Astros' starting rotation.

With left-hander Wandy Rodriguez off the disabled list and set to start Monday's game against the Braves, the Astros optioned reliever Jeff Fulchino to Triple-A Oklahoma City. Aneury Rodriguez, who has made eight starts, was moved back to the bullpen so the 20-year-old Lyles could remain in the rotation.

Lyles, the Astros' top prospect, will start Thursday against the Pirates at Minute Maid Park. He's 0-1 with a 4.15 ERA in three Major League starts.

"I didn't have my mind made up or told myself I should or shouldn't be here," Lyles said. "If they told me I was going somewhere else to pitch, I would get my stuff ready for my next start, wherever it was. You can't control that stuff. I'm happy to be here, and hopefully I'll have another good start."

Aneury Rodriguez, a Rule 5 Draft pick from the Rays, went 0-4 with a 5.80 ERA as a starter after beginning the season in the bullpen. Fulchino is 1-3 with a 4.88 ERA in 30 relief outings, but he's 0-1 with a 12.60 ERA in five innings in his last five games.

"Fulchy's got the stuff and has had some good success here the last couple of years," Astros manager Brad Mills said. "We want him to go down there and be able to work on command of his pitches and be able to throw the ball over the strike zone with consistency."

Bourgeois to have MRI on right ankle Monday

HOUSTON -- Astros backup outfielder Jason Bourgeois will undergo an MRI on Monday morning to try to determine why his right ankle has been causing him problems. Bourgeois, originally scheduled to start in right field in place of Hunter Pence, was scratched from the lineup about an hour before Sunday's game and didn't play.

"It's been killing me to wake up and walk in the morning," Bourgeois said. "In night games, I've been able to get it warmed up and deal with it. It's been tough for me. Today, I woke up and I couldn't take it. I couldn't get warmed up as much as I tried."

Bourgeois started in left field on Saturday and went 1-for-5 with a stolen base. He spent 25 days on the disabled list recently with a strained left oblique, returning to action June 3. He has started five games in center, six in left and one at second base.

"About Thursday morning, I woke up and felt it," he said. "I was able to get warmed up. I kept it under wraps, but it caught up with me."

As a starter, Bourgeois is hitting .400 (20-for-50) with five RBIs and 11 steals, and the Astros are 6-6 in games he's started. He's hit safely in nine of his past 12 games and is fifth in the National League with 12 stolen bases, despite missing nearly a month.

Worth noting

The Astros signed ninth-round Draft pick Jonas Dufek, a right-handed pitcher from Creighton University, on Sunday. The Astros have signed 26 of 50 Draft picks so far, along with signing five non-drafted free agents. Top pick George Springer, a center fielder from the University of Connecticut, is competing in the NCAA Super Regionals.

Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.