Canning pitched two scoreless innings against the Los Angeles Dodgers on Wednesday and had discomfort after coming out of the game, Maddon said.
Maddon acknowledged his concern, saying, “He’s had a history, so of course you’re concerned.”
The 23-year-old right-hander went 5-6 with a 4.58 ERA last season before being shut down in August with elbow inflammation.
The Angels had expected that Canning, a second-round pick out of UCLA in 2017, would take a spot in the rotation this season.
“He’s got a fabulous arm,” Maddon said. “He’s got a great future. We want him well.”