Naughton (forearm) was removed from his rehab appearance Sunday with Triple-A Memphis after throwing just three pitches, Katie Woo of The Athletic reports.
The Cardinals haven't revealed whether Naughton suffered a setback with his strained left forearm in the first outing of his rehab assignment or if he's dealing with a new physical issue, but whatever the case, he didn't end up pitching a full inning for Memphis like the organization had planned. Naughton has been shelved since April 8 with the forearm injury and is eligible to return from the 60-day injured list whenever St. Louis deems him ready to go.