Heller (elbow) has been pulled off his rehab assignment with Triple-A Scranton/Wilkes-Barre, Coley Harvey of ESPN.com reports.
Heller has apparently been feeling something in his elbow/forearm, so the right-hander is headed back to New York to undergo further evaluation. The 27-year-old was nearing a return from 2018 Tommy John surgery before suffering the setback.