McDowell, a Cy Young winner who pitched for the Chicago White Sox, New York Yankees, Cleveland Indians and Anaheim Angels from 1987-99, told Sporting News Radio and the Chicago Sun-Times on Thursday that Prior's slow recovery is a sign of steroid use.
"That's one of the telltale things. What happens with steroids is the muscles get too strong for the tendons," McDowell said.
"He has a tendon injury that's not healing. You shouldn't have a problem like that that doesn't heal in a month. That's what happens to guys who use steroids."
Prior, who probably won't pitch until May because of inflammation in his right Achilles tendon and a stiff elbow, wondered if McDowell was joking.
"Do I look like I'm on steroids?" Prior told MLB.com on Thursday. "That's the first I heard. Was he serious? I guess the best thing I can say is obviously I'm not; I don't know why he would say that.
"I never met the guy, I don't know the guy," he added. "I don't know if he's got a beef with me because I went to (USC) and he went to Stanford. That's about the worst thing I've ever heard. It doesn't even make any sense."
Cubs manager Dusty Baker also scoffed at McDowell's comments.
"How can you just say that?" Baker told MLB.com. "That's pitiful. I have no comment to that other than that's pitiful."
Prior returned to spring training Tuesday after spending Monday
in Chicago, where he had an MRI and bone scan on his Achilles
tendon and right arm.
The 23-year-old right-hander has not pitched in a spring
training game because of the Achilles injury and was already
expected to start the season on the disabled list. Prior has been throwing off a mound this spring.
Both the Cubs and Prior said the MRI and bone scan showed
nothing but inflammation in the heel and elbow.
Prior was 18-6 with a 2.43 ERA and 245 strikeouts in his first
full big-league season last year, finishing third in voting for the
NL Cy Young Award.
Information from The Associated Press was used in this report.