Martinez native Robert Stephenson will make his major league debut when he starts for the Cincinnati Reds on Thursday against the Philadelphia Phillies.

Stephenson, 23, is a hard-throwing right-hander who is regarded as the Reds' top prospect. A graduate of Alhambra High in Martinez, he was Cincinnati's first-round pick in the 2011 amateur draft.

Stephenson tweeted the news of his promotion on Monday.

"this is the day you dream of as a little kid... could not be more excited to be joining the @Reds on Opening Day!! #PlayBall," Stephenson's tweet said.

Stephenson will replace Homer Bailey on the Reds' roster. Bailey, one of the Reds' top pitchers, is recovering from Tommy John surgery.

Stephenson went 8-11 with a 3.83 ERA in the minors last season. He had 140 strikeouts in 134 innings. But Stephenson struggled in spring training this year, with a 9.58 ERA in four starts.