The 24-year-old left-hander experienced tightness in his left forearm during his 2016 debut on April 5, causing his velocity to drop in the later innings and necessitating a trip to the disabled list. Heaney resumed playing catch about 10 days later, but ceased doing so as tightness lingered when he backed up to 90 feet, then sought alternative opinions.
Heaney is on the DL with what the team initially called a flexor muscle strain. Two MRIs have said his ulnar collateral ligament, the one that would require season-ending Tommy John surgery if torn, is sound. Tests have revealed "normal chronic changes to the elbow," which, as Eppler said, "is consistent with a high-level, growing athlete."
But tightness lingers near his elbow.
"It sucks," Heaney said. "I like playing baseball. It's, like, what I do. It's my job. It's what makes me who I am."
PRP injections involve a patient's own blood being drawn and filtered to concentrate the platelets, which attract healing growth factors that can speed up the recovery process. Those platelets are than administered to the affected area.
Still in its relative infancy stages, PRP injections carry minimal side effects and have been used to treat a bevy of pitchers, including Zack Greinke and Masahiro Tanaka.
Heaney, originally acquired from the Dodgers for longtime second baseman Howie Kendrick in December 2014, posted a 3.49 ERA in 18 starts during his rookie season and entered 2016 as the Angels' No. 2 starter.
He is one of three left-handed starting pitchers who have been slow to heal.
Tyler Skaggs, who underwent Tommy John surgery in August 2014, was scratched from his fourth start for Triple-A Salt Lake and is experiencing tightness in his left shoulder, prompting the Angels to schedule an evaluation of him in Los Angeles on Monday.
C.J. Wilson, nursing tendinitis in his shoulder since the start of Spring Training, is still at least a week away from throwing off a mound and won't be back until the middle of June, at the earliest.
Teams inquired about Eppler's starting pitchers throughout the offseason, but the first-year GM never pulled the trigger.
He's happy he didn't.
"I'm glad we walked in with eight," said Eppler, who currently has a staff made up of Garrett Richards, Jered Weaver, Hector Santiago, Matt Shoemaker and Nick Tropeano. "Eight minus three is five."