The surgery cleaned up the labrum and a partial tear of the rotator cuff, and repaired the capsule.
Danny will spend time recovering from the surgery, and will begin rehab as soon as allowed. There is no timetable at this time for his return to the mound.
"This is very unfortunate for Danny and his family, but we have nothing but high hopes for a good recovery and rehab," said Zduriencik. "Danny is a tireless worker and will do everything he can to get back on the mound to start competing again."
Hultzen, 23, made seven minor league starts during the 2013 season, combining to go 5-1 with a 2.02 ERA (8 ER, 35.2 IP). He made his last appearance Sept. 1 for the Tacoma Rainiers (2.0 innings), after missing most of the second half of the Triple-A season.
In two minor league seasons Hultzen has combined to go 14-8 with a 2.82 ERA in 32 starts. He was the No. 2 overall selection in the June 2011 MLB Amateur Draft out of the University of Virginia. He entered this season as the No. 18 overall prospect in baseball by MLB.com.