López made the Red Sox' Opening Day roster in 2007, but after four scoreless outings he was optioned to Pawtucket on April 9 to make room for Mike Timlin, who had started the season on the disabled list.
He was recalled on May 11 when Devern Hansack was sent down.
On this stint, he posted a 3.18 ERA in 40 appearances before getting sent down on August 5 to make room for Curt Schilling, who was returning from the disabled list.
With the Red Sox about to face several tough left-handed hitters in late August, Jon Lester was sent down on August 23 to make room for López on the roster.

In 2007, López made 61 appearances, posting a 2–1 record with a 3.10 ERA in ​40 ²⁄₃ innings.
Despite his three stints in the minors, his 61 appearances ranked second on the club to Hideki Okajima's 66.
He made 17 appearances for Pawtucket, going 2–1 with a 3.78 ERA.
López was a member of the playoff roster for the Red Sox, posting a 15.43 ERA but winning his first World Series as the Red Sox swept the Rockies in four games.
López made the Red Sox' Opening Day roster in 2007, but after four scoreless outings he was optioned to Pawtucket on April 9 to make room for Mike Timlin, who had started the season on the disabled list. He was recalled on May 11 when Devern Hansack was sent down. On this stint, he posted a 3.18 ERA in 40 appearances before getting sent down on August 5 to make room for Curt Schilling, who was returning from the disabled list. With the Red Sox about to face several tough left-handed hitters in late August, Jon Lester was sent down on August 23 to make room for López on the roster. 
In 2007, López made 61 appearances, posting a 2–1 record with a 3.10 ERA in ​40 ²⁄₃ innings. Despite his three stints in the minors, his 61 appearances ranked second on the club to Hideki Okajima's 66. He made 17 appearances for Pawtucket, going 2–1 with a 3.78 ERA. López was a member of the playoff roster for the Red Sox, posting a 15.43 ERA but winning his first World Series as the Red Sox swept the Rockies in four games.
Javier López (baseball)