BOSTON - Red Sox closer Koji Uehara has been activated from the 15-day disabled list after missing Boston's first six games.

To make room on their roster before Monday's home opener against the Washington Nationals, the Red Sox optioned left-hander Tommy Layne to Triple-A Pawtucket.

Uehara was sidelined with a strained left hamstring after appearing in three spring training games. In two seasons with Boston, he has a 10-6 record with 47 saves and a 1.75 ERA and made the AL All-Star team last year.

Asked before the game is his fastball and splitter were ready, Uehara said through an interpreter, "The hitters will tell me, probably."

Layne pitched in four games this season with a 5.79 ERA in 4 2-3 innings.