Cook, 33, suffered the injury during his start against the Orioles yesterday, his first start with Boston. The right-hander was selected to the active roster on Thursday night after going 3-0 with a 1.89 ERA (7 ER/33.1 IP) in five starts with Triple-A Pawtucket to begin the season. Signed by the Red Sox as a minor league free agent in January, Cook owns a 72-69 career record with a 4.56 ERA (666 ER/1,315.0 IP) in 239 Major League appearances, including 207 starts, with the Rockies (2002-11) and Red Sox (2012).
The 26-year-old Miller began the season on the disabled list due to a left hamstring strain. He has made 12 rehab appearances between Single-A Greenville (2 games) and Triple-A Pawtucket (10 games), and has combined to strike out 26 batters in 13.0 innings while posting a 4.85 ERA (7 ER) and collecting one save. Miller appeared in 17 games with the Red Sox in 2011, including 12 starts, and went 6-3 with a 5.54 ERA (40 ER/65.0 IP) and 50 strikeouts. The left-hander allowed three runs or less in eight of his 12 starts and Boston was 9-3 in those outings. Miller, who has appeared in the Majors in all six seasons since being selected by Detroit in the first round (sixth overall) of the 2006 First-Year Player Draft, owns a 21-29 record with a 5.79 ERA (231 ER/359.1 IP) and 288 strikeouts in 96 career appearances (66 starts) with the Tigers (2006-07), Marlins (2008-10) and Red Sox (2011).