Dodgers pitchers and catchers are scheduled to report to the team's Arizona spring training camp Thursday.
Jansen reported discomfort after running last week, and subsequent tests showed a growth on one of the bones in his foot. Doctors removed the growth Tuesday at Cedars-Sinai Medical Center. The Dodgers said Jansen will be on crutches for about 10 days, then in a protective boot for another three to four weeks.
The Dodgers open their season April 6 against the San Diego Padres. Their bullpen already was something of a question mark after they finished with a higher bullpen ERA than all but three National League teams last season.
The Dodgers have no obvious short-term replacement for Jansen on the 40-man roster. Brandon League might be the likeliest candidate given his 74 career saves.
Jansen, 27, had a 2.76 ERA and 1.13 WHIP while saving 44 of his 49 opportunities last year.