This is why key Sunderland defender didn't make squad for Blackpool draw
The Sunderland head coach had said on Monday that he expected the 20-year-old to return to the fold against Blackpool but having decided that he would start the game and with Cirkin still not feeling he had fully recovered, the pair agreed it made little sense to take a gamble.
As such, Mowbray kept Bailey Wright in the squad as his one natural defender on the bench.
"Dennis wasn't quite right," Mowbray explained.
"I had a long chat with him on Monday, I just think he wasn't 100% clear in his own mind that is hamstring is right, and he wouldn't have started tonight's game.
"We just made the decision together that it wasn't worth taking the gamble, the back four wasn't going to change because it's been keeping clean sheets and performing at a good level.
"He has to be ready and work hard in training, he did a really tough session yesterday. When you train you can control the sprints and how hard you push yourself, in a game you can't control that [so it's a risk].
"He's pushing hard in training and I think he's just about there.
"He's going to be eligible I think for the weekend, I expect him to come with us to Swansea City."
Cirkin has been a key player for Sunderland so far this season but Aji Alese has also excelled in his recent absence.