The Boston Red Sox activated Matt Thornton from the 15-day disabled list on Sunday.

Thornton, 36, has been on the disabled list since August 7, retroactive to August 5, with a right oblique strain. Acquired form the White Sox on July 12, he went 0-1 with a 2.16 ERA in 10 appearances for Boston. Overall, the southpaw is 0-4 with a 3.47 ERA in 50 games this season.

To make room for Thornton on the 25-man roster, the Red Sox optioned pitcher Brayan Villarreal to Triple-A Pawtucket. Villarreal, acquired from Detroit in a three-team trade that also sent Jake Peavy from Chicago to Boston, made his lone appearance on Tuesday against the Giants, walking the only batter he faced.