HOUSTON -- Thursday's off-day will allow the Astros to go for a few days without having a fifth starter. Aneury Rodriguez made a cameo start on Tuesday, allowing two solo home runs in six innings against the Marlins, and was sent back down to Triple-A Oklahoma City. The Astros will need to call up a starter for Tuesday's game in Philadelphia.

Rodriguez won't be eligible to make that start because he has to stay in the Minors for 10 days, but right-hander Jordan Lyles could be brought back. Lyles made a spot start April 29 in Cincinnati, allowing four hits and three runs in six innings, and was shipped right back to Oklahoma City.

"It's kind of tough now when you look at those two performances to gauge where we're at," Astros manager Brad Mills said. "It's outstanding that both of those guys are progressing, and there's no doubt the way baseball is, we'll probably see them again fairly soon."

Lyles, 21, is 4-0 with a 4.22 ERA in five starts at Oklahoma City, and last pitched on Saturday. He was 2-8 with a 5.36 ERA in 20 games, including 15 starts, for the Astros last year.

Martinez out of lineup, could get few days off

HOUSTON -- Astros manager Brad Mills kept struggling left fielder J.D. Martinez out of the starting lineup for Wednesday's series finale against the Marlins, and said he might give him a few more days off. Martinez entered Wednesday in a 1-for-30 slump.

"It's not a punishment," Mills said. "I'm just going to give him a couple of days. This will get me a chance to get [Justin] Maxwell some at-bats, and [Travis] Buck's gotten a few at-bats. But more than anything else, it will let him take a breath and get the feel back of maybe being stronger and so forth. I'm not going to sit here and put that in stone. We'll just let him relax a little bit and go from there."

Martinez burst onto the scene last year after being called up from Double-A Corpus Christi when Hunter Pence was traded in late July. He hit .274 with six homers and 35 RBIs, including an Astros rookie record 28 RBIs in the month of July.

Martinez got off to a nice start this year, and was hitting .313 with three homers and 18 RBIs and a .432 on-base percentage before beginning his slide.

"He wants to play every day, and most of the guys [who aren't in the lineup] aren't going to understand, and that's fine," Mills said. "I love him to death. We all love him to death with what he did last year and the first part of this year and what he's capable of. Let's allow him to go through the process. That's where I'm at."

Mills pleasantly surprised by consistent Lowrie

HOUSTON -- Even before Astros manager Brad Mills got to know Jed Lowrie when he was the bench coach of the Boston Red Sox and Lowrie was a part-time infielder, he saw him play in college and was immediately impressed.

That's why Mills isn't surprised to see Lowrie do so well this year. The shortstop entered Wednesday hitting .307 with a team-high four homers and 12 RBIs, and had yet to make an error before misplaying a ball in the first inning Wednesday. But Mills is somewhat surprised to see Lowrie be so consistent.

"I hadn't seen that," the manager said. "He wasn't the everyday guy when I was [in Boston], but I knew the ability was there. I knew the ability was there in college."

Mills got a close-up look at Lowrie while he was a player at Stanford, and Mills' son, Beau, was playing for Fresno State. Beau Mills is currently playing at Triple-A Columbus in the Indians' system.

"I saw him play, and I said, 'That guy is going to be a pretty good player,'" Mills said. "People said he was going to be a high draft pick. I saw him hit two home runs in one game in college -- one from each side of the plate. We knew he had some ability then, and when he was with Boston, we knew he had that ability, but to do it on a consistent basis, I hadn't seen that."

Houston 'pen enjoying dramatic improvement

HOUSTON -- The Astros' bullpen entered play Wednesday ranked third in the National League with a 2.80 ERA, a vast improvement over the struggles the team endured in the 'pen a year ago, when it led the league with 25 blown saves.

Another year of experience for guys like David Carpenter and Fernando Rodriguez has helped the bullpen, but the presence of veterans Brett Myers and Brandon Lyon has also paid dividends. Lyon wasn't around much last year after having season-ending surgery in the first half of the season, and Myers was moved to the bullpen after starting the previous two years.

"Any time you get some veteran guys down there like that, it's good," Astros manager Brad Mills said. "What's nice is they have each other, as well, so they don't feel like they're by themselves down there."

Rodriguez, who's in his second year with the Astros, credited both Lyon and Myers with helping him personally and changing the mindset of the bullpen as a whole. The relievers even have a nickname this year, "The Regulators."

"I had a talk with both of them that game in I lost in Cincinnati on a home run [April 29], and the next day they came up to me and said, 'I'm not going to tell you that you threw the wrong pitch or did something wrong, but I wanted to know what you're thinking,'" Rodriguez said. "Myers brings a totally different attitude to the bullpen. After he comes down to the bullpen, everybody gets their game face on. It's serious down there, where last year you had guys that were still in the sixth inning and joking around. Once he gets down there, it's time to go."

Worth noting

Astros pitcher Kyle Weiland, who underwent surgery May 1 to clear up an infection in his right shoulder, began his rehab Wednesday by doing range-of-motion exercises. He's aiming to be able to throw a baseball in four weeks, with hopes of contributing in the second half of the season.