Sunderland rocked by injury blow with defender facing six months out
Assessments of the injury he picked up at Shrewsbury Town on Tuesday night have confirmed the worst for Sunderland, who will be without one of their most consistent players for the final stages of their promotion campaign.
The 26-year-old will now undergo surgery as he starts his rehabilitation.
“It’s a minimum of six months out, probably,” Johnson said.
“It is a rupture of the tendon as I suspected and he’s going to have surgery.
“I really feel for him, he’s a really good player and it’s a huge loss for us. He’s got that Championship power and physicality that you need.
“He’s been nursing it for a long time and I feel for him because he’s a good lad and a big part of our squad.”
Johnson also confirmed that Ross Stewart will not be able to make his debut when Doncaster Rovers visit the Stadium of Light on Saturday.
Stewart has been recovering from a hamstring problem picked up in the latter days of his time at Ross County.
Johnson is hopeful that the 24-year-old will be back in action soon, but looks unlikely to be available until the trip to Burton Albion next weekend at the earliest.
“He’s slipped in one of the training drills that he was doing,” Johnson said.
“It’s a setback, not a bad one, he’s just going to have a scan.
“He’s just a felt a bit of tightness so best-case scenario, it’s just a bit of scar tissue and after the scan we can up it again.
“It’s probably going to be a week to ten days.”
Dion Sanderson looks likely to start on Saturday, with Tom Flanagan still recovering from a minor calf problem that forced him to pull out of the 2-2 draw with MK Dons last Saturday.
Sunderland’s head coach could have Callum McFadzean and Carl Winchester available again, pending a late fitness test.
“Tom Flanagan is unavailable,” Johnson said.
“Denver Hume is still a couple of months away with his long-term injury.
“Callum McFadzean and Carl Winchester are both better and we’ll test them ahead of the game.”