Right-hander Mat Latos takes the mound for Cincinnati in Sunday's series finale at Great American Ball Park, as the right-hander looks to build off of his first win in a Reds uniform.
Lyles, 20, is expected to start in place of injured right-hander Kyle Weiland, who landed on the disabled list on Friday. After struggling in Spring Training -- where he allowed 19 earned runs in 20 1/3 innings -- Lyles seems to have figured things out at Triple-A Oklahoma City. The right-hander led the Pacific Coast League with four wins, while posting a 3.46 ERA with 24 strikeouts -- compared to only four walks -- in 26 innings.
Lyles said the biggest difference between now and Spring Training is his curveball, which has helped his entire repertoire.
"My velocity's been up a little bit since I've been down, and the curveball's made strides," said Lyles, who went 2-8 with a 5.36 ERA with Houston last season. "I think that was the pitch that was holding me back last year. I didn't really have good command of it or good trust in it. Now I do."
Latos takes the mound trying to help the Reds win their third straight series. The 24-year-old tossed seven shutout innings against the Giants his last time out, and not only posted his first win the season, but also threw his first quality start.
After his last outing, Latos admitted the offseason trade that brought him over from San Diego -- in which the Reds gave up four players -- had been in the back of his mind. At the end of the day, he said, he simply has to focus on what he can control.
"Who's to say I am worth four players? But who is to say that I am not?" Latos said. "Just to look back at the trade, you say, 'Wow, I just got traded for four guys.' Obviously I meant a lot to them. It's a blessing to have it happen.
"It's always in the back of your mind thinking about, 'If I come here and I don't perform, then I'm going to have a long season ahead of me.' It just goes back to not being too perfect, trying to execute my pitches and giving it all I've got."
Latos will have history on his side Sunday, as he is 3-1 with a 2.30 ERA in four career starts against the Astros. With Houston's Carlos Lee (sprained left ankle) likely out, Chris Johnson is the only Astros player with a hit against the right-hander.
Astros: Schafer still streaking
Outfielder Jordan Schafer has reached base safely in all 21 games this season. The streak is the longest to open a season by an Astros hitter since Ricky Gutierrez had a 23-game stretch in 1998. The club record is 25, set by Denis Menke in 1969.
A corresponding roster move will be made before Sunday's game to make room for Lyles.
Reds: Milestones within reach
Third baseman Scott Rolen's next double will be the 505th of his career, tying him with Hall of Famer Tony Perez for 49th on the all-time list. Two more doubles would tie Rolen with Babe Ruth for 48th all-time.
With his next home run, first baseman Joey Votto will tie Sean Casey for fourth on the Reds' all-time list for most home runs hit as a first baseman. Votto is sitting on 116 homers.
One of Lyles' two victories last season came against the Reds on Aug. 3, when he allowed three runs on six hits in seven innings.
Astros pitchers have a 3.38 ERA in day games.
Left-handed batters are 0-for-12 against Astros lefty Wesley Wright this season.