Jordan Lyles is in the midst of a five-way competition for the Astros' final rotation spot. Sunday's performance probably didn't hurt his chances at all.

Lyles garnered four more strikeouts -- he has nine over his last 8 2/3 innings -- in a relief appearance for the Astros, who fell 3-1 to the Pirates.

The top pitching prospect in the Houston system allowed a run on a pair of hits without walking a batter over 3 2/3 innings.

Lyles entered in the third inning with the Astros down two runs. He got Neil Walker to fly out to center field and struck out Matt Diaz, but Andy Marte singled to left and Ryan Doumit's first triple plated the first run Lyles has given up since March 9. The right-hander got Josh Fields on strikes to get out of the inning.

After plowing through the first two hitters of the fourth, Lyles muffed a Jose Tabata comebacker. No further damage was done, though, as he induced a fly ball off the bat of Steve Pearce. He turned in a perfect fifth and got the first two hitters of the sixth -- including Ryan Doumit on strikes -- before giving way to Wesley Wright.

"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," Lyles told MLB.com. "My cutter was good today. [Catcher Humberto Quintero] 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. I needed a strikeout, and I made it a little bit bigger. But overall, I feel like my stuff was all right."

Lyles also did his part at the plate, delivering a successful sacrifice bunt in the third and a line-drive single up the middle in the fifth.

The 20-year-old, who was named MLB.com's No. 31 prospect this offseason, came to the Houston system as a supplemental first-round pick in the 2009 Draft. He was 7-12 with a 3.57 ERA with 137 strikeouts last year between Double-A and Triple-A. He turned in a perfect two-inning performance, striking out three, against the Orioles on Tuesday.

J.B. Shuck, Carlos Corporan, Collin DeLome and Koby Clemens got into the game for the Astros. None of the prospects produced a hit, with Clemens not even getting into the batter's box.

Pirates righty prospect Michael Crotta grabbed his first Grapefruit League save, allowing an unearned run over a ninth-inning appearance. He's otherwise unscored upon over 9 1/3 frames this spring.