Astros top pitching prospect Jarred Cosart was finally able to get back on the mound on Sunday following a 17-day layoff because of a blister he had developed on his right thumb.

Cosart threw five scoreless innings for Double-A Corpus Christi, striking out four batters and allowing four hits while throwing 74 pitches in a 5-3 win over Frisco. The results were nice, but the most important thing for Cosart was that his thumb responded well.

"Obviously, No. 1 was I was able to get through five with the finger staying intact," Cosart said. "That was the biggest thing. From the competitive side, I wanted to give my team a chance to win and do well. I was able to mix my pitches and it was all pretty good."

Cosart was throwing hard, hitting 100-mph on a couple of occasions, and relied mostly on his fastball and curveball. Being a hard-thrower is one of the reasons why Cosart has had trouble with blisters, which he says he gets every year.

"The last two years they have been on my middle finger and this year on my thumb," Cosart said. "The trainers just say being a high-velocity guy, I put a lot of friction on the seam, and the humidity down here and stuff doesn't help."

Among the treatments, Cosart is putting his finger in a bucket of rice and putting dry grip on the blister.

"You want to try to avoid it getting cut open," Cosart said. "I'm going to keep doing that even when I don't have blisters. I only get them once a year, but it's an annoying injury to have. The finger still being intact means I can make another start."

Cosart, acquired in last year's Hunter Pence trade with the Phillies, has pitched 9 1/3 innings in two starts and has allowed eight hits, no runs and struck out nine.

Oklahoma City hurlers impressive early on

Led by Jordan Lyles, left-hander Dallas Keuchel, Henry Sosa and Paul Clemens, the starting pitching staff at Triple-A Oklahoma City continues to impress. RedHawks starting pitchers were 9-2 with a 2.14 ERA before Aneury Rodriguez and Ross Seaton were roughed up in starts against Albuquerque on Saturday and Sunday, respectively.

"We've got some guys doing well," pitching coach Burt Hooton said. "We've only played two teams in Nashville and Memphis [prior to Saturday]. After a while, you start to figure some things out. Plus, they may not be the strongest teams in the league."

Keuchel will take a 3-0 record and 0.90 ERA in three starts into Monday's game against Albuquerque. Lyles (3-0, 2.89 ERA), Sosa (1-0, 1.69 ERA) and Clemens (1-1, 1.59 ERA) have also excelled through three starts, though Clemens is on the disabled list with back spasms. Rodriguez is 1-2 with a 5.89 ERA in four starts.

"I'm still expecting Aneury to pick it up," Hooton said. "Lyles is 3-0 for the first time in his career and, hopefully, he'll be 4-0 after [Tuesday] night."

Seaton came up from Double-A Corpus Christi to start on Sunday against Albuquerque and gave up seven hits, six runs (five earned) and walked two batters in 4 2/3 innings. On Monday, he was sent back to the Hooks and Jonnathan Aristil was called up, giving the RedHawks another bullpen arm after using five relievers in Sunday's 14-inning loss.

Bixler swinging a hot bat at Triple-A

Versatile infielder/outfielder Brian Bixler, who was the Astros' last cut prior to setting their 25-man roster, has gotten off to a terrific start at the plate at Triple-A Oklahoma City.

Bixler has hit safely in each of his first nine games, going 20-for-40 and reaching base in 25 of his first 43 plate appearances. Despite playing in just half of the team's total games, he leads the team in hits and has six stolen bases. In addition to the hot bat, Bixler has provided versatility, making starts at five different positions -- second base, third base, shortstop, left field and center field.

"He is what we expected him to be, which is a very versatile player," Astros director of player development Fred Nelson said. "He has shown the ability to drive the ball, not only in the gaps, but also out of the park, which is refreshing.

"He's a nice piece. And if somebody goes down, he's a guy -- along with Brett Wallace and Jimmy Paredes -- that could come and help the big league club."

Paredes has four multi-hit games and is hitting .423 (11-for-26) over his last six games. All five of his extra-base hits and five of his six RBIs for the year have occurred during this stretch.

Worth noting

• Right-handed reliever Josh Zeid, who's on the disabled list at Corpus Christi with elbow tenderness, was scheduled to undergo a precautionary MRI on Monday. Pending a good result, he could return to action in a week. Zeid has only pitched in three games.

• After a pair of rough outings in his first two starts at Corpus Christi, left-hander Brett Oberholtzer threw seven scoreless innings and struck out eight on Friday against Frisco. "He was outstanding," Nelson said. "He had command of the zone, threw his slider and curveball in and out. I think that was very encouraging."

• Right-hander Mike Foltynewicz, the Astros' first-round pick in 2010, is off to a good start at Class A Lexington. He's 3-1 with a 1.66 ERA in four starts, with 23 strikeouts in 21 2/3 innings.

• Class A Lancaster right-handed starter David Martinez (0-1, 6.52 ERA in four starts) is on the disabled list with a blister and is expected to miss one start.