Jansen is expected to be at Dodger Stadium on Friday night for the opening of a three-game series with Arizona and will be re-evaluated to determine when he can return to the mound.
The 23-year-old Jansen complained of a heart "flutter" after saving Tuesday night's game, according to manager Don Mattingly. After being administered an EKG, Jansen was hospitalized and underwent a cardio conversion to get rhythm back to his heartbeat by shocking it with electrodes.
Trainer Stan Conte said Joe Beimel received the same treatment a couple years ago and pitched two days later.
After a shaky start to the season and a three-week stint on the disabled list for a sore right shoulder, Jansen has been one of the most effective relievers in the game over the past six weeks. Since returning from the disabled list on June 18, he has struck out 26 over 16 scoreless innings, holding the opposition to a .059 batting average (3-for-51).
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.