Rusney Castillo, Jackie Bradley Jr. Sent to Minors

The Boston Red Sox have optioned Rusney Castillo and Jackie Bradley Jr. to Triple-A Pawtucket, clearing the way for Mookie Betts to be the opening-day starter in center field.

With a glut of outfielders in spring training, the Red Sox pared down the group Thursday. They will begin the regular season with Hanley Ramirez in left field, Betts in center and Shane Victorino in right.

Daniel Nava and Allen Craig are likely to remain on the big league roster and can play the outfield as well.

Castillo, who signed a $72.5 million, seven-year contract with Boston last year after defecting from Cuba, missed two weeks of spring training with a sore oblique muscle.

Bradley, a standout defender, struggled at the plate last season.

Betts, a touted prospect and converted infielder who made a successful major league debut last year, began the day batting .458 in spring training. He was tied for the Grapefruit League lead with 22 hits.