BOSTON, MA - The Boston Red Sox today selected infielder/outfielder Mookie Betts to the active major league roster from Triple-A Pawtucket. To make room for him on the 25-man roster, right-handed pitcher Rubby De La Rosa was optioned to Pawtucket. Betts will wear No. 50 and will be active for tonight's 7:15 p.m. game at Yankee Stadium. With this move, the Red Sox' 40-man roster is now at 39.

Executive Vice President/General Manager Ben Cherington made the announcement.

For Betts, 21, this is his first career major league stint. He has reached base safely in 71 of 77 games this season between Double-A Portland and Triple-A Pawtucket, batting .345 (105-for-304) with 21 doubles, four triples, eight home runs, 48 RBI, 70 runs scored, 29 stolen bases, a .437 on-base percentage, and a .520 slugging percentage en route to a spot on the 2014 XM Sirius All-Star Futures Team. Betts reached base safely in all 23 career Triple-A games, with a .322 average (29-for-90), 16 walks, and a .425 on-base percentage for the PawSox after a June 3 promotion from Portland, where he led the Eastern League in batting (.355), hits (76), and runs scored (56) in 54 games to begin the season. Between the two stops this season, the native of Brentwood, TN has played 45 games at second base, as well as 27 in centerfield and two in right field for his first outfield experience as a professional. The right-handed batter reached base safely in 71 consecutive games, including regular and postseason, between 2013 and 2014, a streak that ended on May 17. Last season, Betts hit .314 with 36 doubles, four triples, 15 homers, 81 walks, and 38 stolen bases last season in 127 contests between Single-A Greenville and High-A Salem and was named 2013 Red Sox Minor League Offensive Player of the Year. Signed by the Red Sox as a fifth-round selection in the 2011 June Draft, he has hit .312 (319-for-1,021) with a .408 on-base percentage in 276 minor league games over four seasons in Boston's farm system.

De La Rosa, 25, was recalled on May 31 and made five starts for the Red Sox, going 2-2 with a 2.51 ERA (9 ER/32.1 IP) and 30 strikeouts compared to just eight walks and 25 hits allowed. With the PawSox this season, he is 2-3 with a 3.04 ERA (18 ER/53.1 IP) and 52 strikeouts in 10 appearances, all starts. The right-hander was acquired by Boston on August 25, 2012 as part of a nine-player trade with the Los Angeles Dodgers. In 30 career major league appearances (15 starts) between the Dodgers (2011-12) and Red Sox (2013-14), he is 6-9 with a 3.69 ERA (43 ER/105.0 IP) and 96 strikeouts.