The Red Sox have signed knuckleballer Charlie Haeger, reports Kevin Goldstein of Baseball Prospectus. (Twitter link) Haeger was released by the Mariners last week after posting a 7.74 ERA in nine starts with Triple-A Tacoma. Haeger has also pitched for the White Sox, Padres and Dodgers, amassing a career 6.40 ERA in 83 Major League innings spread over five seasons.