Sources: Red Sox agree with Cook

The Red Sox, taking a step toward upgrading their rotation, have reached agreement with free-agent right-hander Aaron Cook on a minor league contract, according to major league sources.

The deal, which will become official when Cook passes a physical, includes an invitation to spring training, the sources said.

Cook, 32, is familiar with new Red Sox pitching coach Bob McClure, who worked in the Rockies’ organization from 1999 to 2005. Cook was the Rockies’ second-round pick in ’97, and pitched for them in the majors from ’02 to ’11.

With Cook, the issue is staying healthy. He was down with a shoulder ailment last spring when he broke the tip of a finger in his right hand in a door. He returned in June and went 3-10 with a 6.03 ERA the rest of the season.

In 2010, he missed time with turf toe and a broken right leg that he suffered on a line drive by the Reds’ Joey Votto. In 2009, he was out for more than a month with a strained right shoulder.

Cook, though, is the Rockies’ all-time leader with 72 wins, and at his best is an effective sinkerballer. He was 16-9 with a 3.96 ERA in 2008 and 11-6 with a 4.16 ERA in ’09.

The Rockies declined their end of an $11 million mutual option on Cook at the end of the season. He went only 20-24 with a 4.94 ERA during his three-year, $30 million contract from 2009 to ’11, making 68 appearances, 67 of them starts.