Cubs reliever Brad Wieck underwent a cardiac ablation procedure on Monday for an abnormal heartbeat, the club announced on Thursday.
Cubs head physician Dr. Stephen Adams discovered an intermittent atrial flutter during Wieck's pre-spring training physical earlier this month. The left-hander returned to Chicago and underwent a procedure on Monday at Northwestern Memorial Hospital to prevent a recurrence of the flutter.
Wieck returned to Arizona on Wednesday and will rest for the next week or so. The Cubs will then determine when the 28-year-old will begin his throwing program.
Former Cub Mark DeRosa underwent a similar procedure in spring training 2008 and did not miss the start of the season.