That season is going to be on hold "indefinitely", according to ESPN Los Angeles:
Dodgers manager Don Mattingly revealed Jansen's condition Wednesday, stating that the star reliever is experiencing issues related to an irregular heartbeat that sidelined him for a month last season.
Jansen was hospitalized Tuesday and has not given the Dodgers permission to discuss details of his condition. He was required to take blood thinners last season to treat the irregular heartbeat, forcing him to spend time on the disabled list.
The article mentions that the Dodgers could use the recently-acquired Brandon League at closer; League has closing experience, also noting that Ronald Belisario posted a five-out save against the Rockies Wednesday. Javy Guerra, who had eight saves earlier this year for the Dodgers, was recently optioned to Triple-A Albuquerque, but could be recalled after rosters expand September 1.