WEST PALM BEACH, Fla. -- Top prospectFrancis Martes will get the start for the Astros on Saturday against the Marlins at the Ballpark of the Palm Beaches after veteran right-hander Mike Fiers developed a sore right hamstring, manager A.J. Hinch said Friday.Fiers came down with right hamstring soreness while running

WEST PALM BEACH, Fla. -- Top prospect Francis Martes will get the start for the Astros on Saturday against the Marlins at the Ballpark of the Palm Beaches after veteran right-hander Mike Fiers developed a sore right hamstring, manager A.J. Hinch said Friday.

Fiers came down with right hamstring soreness while running sprints Thursday, and he is having his turn in the rotation skipped as a precaution. Fiers said he feels he could have pitched and that it shouldn't affect his readiness for the start of the season.

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"I guess it's normal for working out every day, and you get some bumps and bruises here and there," said Fiers, who's battling with Joe Musgrove for the fifth spot in the rotation. "And I guess [Hinch] just wants to be cautious of it and take it a day at a time and not really push it."

Martes, ranked as the No. 20 prospect overall by MLBPipeline.com, will pitch two or three innings against the Marlins, and he will be followed by Chris Devenski . Martes struck out 131 in 125 1/3 innings at Double-A Corpus Christi last year, going 9-6 with a 3.30 ERA as the youngest pitcher (20 years old) in the Texas League.

"We want to give him a start and let him have a normal prep," Hinch said. "Obviously, it's unfortunate Fiers is going to miss a start. It will be nice to have Martes have a normal pregame and the look and feel of a start in Spring Training."