Naughton will be evaluated after he "felt a tug" in his left forearm during his first rehab appearance with Triple-A Memphis on Sunday, Cardinals manager Oliver Marmol told Jeff Jones of the Belleville News-Democrat on Monday.
Naughton lasted just three pitches before suffering the setback. He's missed nearly all of the season with the arm issue and clearly isn't going to be rejoining the St. Louis bullpen anytime soon.