Anderson, 23, underwent the injection at the recommendation of noted orthopedic surgeon Dr. James Andrews, to whom he paid a visit in Pensacola, Fla., on Monday for a second opinion. According to a team statement, the A's southpaw will be reevaluated in three weeks.
Given Andrews' suggestion, it's likely Anderson is experiencing either elbow tendinitis or inflammation. He suffered the latter problem twice last season and was subsequently forced to endure a pair of trips to the disabled list that limited him to just 19 starts.
A handful of A's players have experienced successful results from PRP in the past, including outfielder Ryan Sweeney (knee) and right-hander Joey Devine (elbow).
Anderson, who was placed on the 15-day DL on Tuesday, struggled in his last two starts, surrendering a combined 14 earned runs against the Yankees and Red Sox, along with four home runs and five walks, in just 10 1/3 innings. Following a loss in Boston on June 5, he noted his slider -- normally his best pitch -- has not been as sharp as normal and he has not thrown with his usual velocity. He is 3-6 with a 4.00 ERA in 13 starts this year.
The A's are hopeful Anderson's rehab doesn't extend much longer than the six-week mark, because they have already lost three other starters to injury. That number doesn't even include Rich Harden, who has yet to pitch in a game. Lefty Dallas Braden is out for the year after undergoing shoulder surgery, and right-handers Brandon McCarthy (shoulder) and Tyson Ross (oblique) are expected to be sidelined for at least another month.