New York Yankees ace Gerrit Cole has been shut down and visited specialist Dr. Neal ElAttrache in Los Angeles on Wednesday for further testing on his right elbow.

Manager Aaron Boone said he has no timetable for how long Cole will be sidelined. Cole has already been ruled out for Opening Day and is expected to begin the season on the injured list.

Cole underwent an MRI on the elbow in Florida earlier in the week after reporting “discomfort.” Boone told reporters Wednesday that Cole did not bounce back as expected between outings.

“His recovery, before getting to his next start, has been more akin to what he feels during the season, when he’s making 100 pitches,” Boone told reporters. “When he’s at 45 [pitches] and building to 55, he usually doesn’t have the recovery issues he’s having.

“I think there’s a level of discomfort, but I wouldn’t describe it as he’s in pain.”

Cole, 33, was slated to make his second spring training start Tuesday. He gave up three runs over two-plus innings in his first outing March 1 against the Toronto Blue Jays. He threw 47 pitches across three innings in a simulated game facing Yankees hitters six days later. He did not report any discomfort when he talked with reporters afterward.

Cole previously landed on the injured list with elbow inflammation in September 2016 while with the Pittsburgh Pirates. The reigning Cy Young Award winner is in the fifth year of a nine-year, $324 million contract.