Prior, who has battled career-threatening arm and shoulder problems, hasn't pitched in the majors since 2006.
"I still have an opportunity," Prior told MLB.com. "I don't necessarily feel like a martyr or something because I've worked hard and I should be paid with an opportunity, but I'm grateful for it. I don't take it for granted. I'll do everything I can to go out and perform and try for a spot."
Ironically, Baker was criticized by some for contributing to Prior's arm troubles during their time together in Chicago. Now he may be Prior's best chance for one last shot.
"He said ‘hey man, I'd like to try it one more time,'" Baker told reporters. "I said I would try to make the opportunity available to you."