Roethlisberger has played with the injury for a few weeks -- it didn't occur during last Sunday's 19-16 overtime victory over the Bills -- though the exact date of the original fracture is unknown. Sunday's pounding -- Roethlisberger was sacked five times -- exacerbated the injury.
Roethlisberger is in a lot of pain, leading him to wear a boot early in the week, but he'll be able to play, according to the source.
Roethlisberger was limited in practice Thursday, but he said he fully expects to play when the team visits the Baltimore Ravens this weekend. Steelers offensive coordinator Bruce Arians told the Post-Gazette on Thursday that Roethlisberger's injury shouldn't curtail anything he does on the field against the Ravens.
The Associated Press contributed to this report.