Prior, who was making $15,000 a month on a Minor League contract he signed with the Padres in January, had a setback in late April when he reported soreness in his shoulder while rehabilitating in Arizona.
Prior, who will be released from his Minor League contract, possibly as soon as Saturday, hadn't reached the point where he was throwing to live hitters when he reported soreness in his shoulder.
"The poor guy just can't seem to get over the hump. He is doing everything possible for him to come back. ... I hope it works out for him," Padres manager Bud Black said at the time of the setback.
Prior, who is a San Diego native, was trying to return to the Major Leagues after the two surgeries to his right shoulder, the first in 2007 by renowned orthopedic surgeon Dr. James Andrews to repair a 180-degree tear of his labrum as well as a split of the shoulder capsule.
Then, on the heels of a year-long recovery and rehabilitation program, Prior suffered a serious setback when he tore the anterior capsule in his shoulder, a gruesome injury of sorts that saw the capsule tear away from the humerus bone. He had surgery last June.
Doctors informed Prior that such injuries were not only uncommon among pitchers, but went as far to add that this particular injury is "often associated with traumatic events ... typically from a fall."
Prior was on his second Minor League contract with the team. His original contract, the one he signed in December 2007, was for $1 million.
Prior, 28, hasn't pitched at the Major League level since 2006. He was an innings-eater from 2002-05 with the Cubs, throwing 613 innings with a 3.24 ERA, including 2003, when he went 18-6 with a 2.43 ERA.
Despite the injuries, Prior said during Spring Training that he was determined to make it back to pitching in the Major Leagues.
"If I can get back to 80 percent or 90 percent of what I used to be, then that's still pretty good. I look back to those three, four years in the big leagues, and I pitched pretty well and did the things I had to do to help us win games," Prior said. "I don't know if those memories haunt me, but they motivate me."
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.