The announcement was made by Executive Vice President/General Manager Ben Cherington.
Hill, 32, was placed on the 15-day disabled list on April 4 (retroactive to March 26) recovering from Tommy John surgery to reconstruct a torn ulnar collateral ligament in his left arm, a procedure he underwent on June 9, 2011. He combined for a 2.00 ERA (2 ER/9.0 IP) and 18 strikeouts with just five hits and two walks allowed in eight minor league rehab outings this season, including two with Single-A Greenville and three each with High-A Salem and Triple-A Pawtucket. A Boston native, Hill has held opponents scoreless in all 15 outings with the Red Sox dating back to September 14, 2010, the longest streak ever to begin a Sox career. In 93 career Major League appearances (70 starts) between the Cubs (2005-08), Orioles (2009) and Red Sox (2010-11), the left-hander owns a 22-20 record with a 4.73 ERA (214 ER/407.1 IP) and 370 strikeouts.
The 28-year-old Thomas has appeared in seven games for the Red Sox this season, all in relief, allowing four runs in 4.2 innings (7.71 ERA) with four strikeouts, two walks and 10 hits allowed. A fourth-round selection by Seattle in the 2005 First-Year Player Draft, Thomas has made 27 Major League appearances out of the bullpen between the Mariners (2008), Pirates (2010) and Red Sox (2012), going 0-2 with a 6.65 ERA (16 ER/21.2 IP) and 11 strikeouts. He is 45-35 with 14 saves, a 4.15 ERA (306 ER/664.1 IP), 600 strikeouts and 282 walks allowed in 258 career minor league games (76 starts).