Butler, 26, split 2012 between Portland and Pawtucket, hitting .247 (79-for-320) with 19 doubles, two triples, nine home runs, 37 RBI, 37 runs and 40 walks in 95 games. Between the two stops, he threw out 38 of 114 attempted base stealers (33.3%). He played a career-high 22 games at the Triple-A level after a promotion on August 3, and also appeared in six postseason games for the PawSox, going 6-for-19 (.316) with a homer. In 330 games over parts of four seasons in the Red Sox system, the right-handed batter has hit .259 (288-for-1,114) with 77 doubles, six triples, 29 home runs and 166 RBI. He was named to minor league All-Star teams with the Drive in 2010, and again in 2011 with the Salem Red Sox, his first two full professional campaigns after signing with Boston as a non-drafted free agent in July 2009. Currently, Butler is playing for Toros del Este of the Dominican Winter League.
A native of Milton, MA, Hassan spent the 2012 season with Pawtucket and played in 94 games, appearing in left field, right field and at designated hitter. He topped all PawSox with at least 125 plate appearances with a .377 on-base percentage and finished second on the team with 55 walks, the 12th-highest total in the International League. Following the season, he was ranked by Baseball America as having the best strike-zone judgment in the circuit. A right-handed batter, he hit at a .256 clip (80-for-312) with 13 doubles, seven home runs, 46 RBI and 39 runs this past season. Selected by the Red Sox in the 20th round of the 2009 First-Year Player Draft out of Duke, Hassan has hit at a .284 clip (351-for-1,236) with 83 doubles, six triples, 30 home runs, 177 RBI, 180 runs and 198 walks in 361 career minor league games in the Boston system. He had a brief stint with the Drive in 2009, batting .313 (10-for-32) with a homer, 7 RBI, and 6 runs scored in 8 games.
Vazquez, 22, played the majority of last season with High-A Salem, where he was a Carolina League Postseason All-Star. He was also tabbed by Baseball America as the best defensive catcher in the league after leading catching qualifiers with a 41.9% caught stealing percentage (44 of 105) and 110 assists. Vazquez ended the year with 20 games for Portland in his Double-A debut and batted .254 (93-for-366) with 21 doubles, seven homers, 46 RBI, 54 runs and 48 walks across the two levels, including a .291 clip (51-for-175) over his last 48 games. He threw out 49 of 122 base stealers (40.2%) overall, and following the season was named by Baseball America as the best defensive catcher in the Red Sox farm system for a second straight year. Selected in the ninth round of the 2008 First-Year Player Draft, the right-handed batter has hit .256 (304-for-1,187) with 67 doubles, three triples, 30 home runs and 183 RBI in 337 career games over five minor league campaigns. He began the offseason in the Arizona Fall League and is now playing in the Puerto Rican Winter League.
With the addition of Butler, Hassan, and Vazquez, Boston's 40-man roster consists of 11 former Drive players - pitchers Daniel Bard, Drake Britton, Clay Buchholz, Felix Doubront, and Stolmy Pimentel; catchers Dan Butler, Ryan Lavarnway, and Christian Vazquez; infielder Will Middlebrooks; outfielders Alex Hassan and Ryan Kalish - and 4 who made Major League rehab assignments in Greenville - pitchers Chris Carpenter, Rich Hill, Jon Lester, and Andrew Miller.