The Houston Astros have called up top pitching prospect Francis Martes, who they are expected to break in out of the bullpen.

Martes, 21, was part of the trade with the Miami Marlins that sent Jarred Cosart to the Marlins and Jake Marisnick to the Astros.

Baseball America ranked Martes as the No. 17 prospect entering the season. Martes has started eight games for Triple-A Fresno this season, going 0-2 with a 5.29 ERA, 2.10 WHIP and 38 strikeouts in 32 1/3 innings.