Elliot Embleton's return has been delayed with Phil Parkinson revealing the youngster has picked up a series of 'little niggles' which have held him back.
The 21-year-old impressed Parkinson in pre-season before suffering a thigh problem in the Black Cats' friendly against Gateshead in August, and has not figured since.
Embleton was due to return to full training last month and fans had hoped he would be involved in Sunderland's EFL Trophy game against Carlisle United last night, but he was not in the squad.
And after the game Parkinson said that the academy graduate's progress had been disrupted, and said he would not be rushed back until he is fully ready.
"Elliot keeps picking up little niggles at the moment which are setting him back, and that's a frustration for him," Parkinson said.
"We are just going to take it very slowly with him and make sure he has enough training, and gametime at U23 level, so that he is ready.
"It's a shame because he had a good pre-season, but I'm sure he will make a big contribution this season.
"He's just not quite ready yet."
Embleton also missed a large chunk of last season with a serious hamstring injury which ruled him out from September until March, with the campaign's premature end denying him a comeback.
Parkinson also has an injury concern over striker Will Grigg who was absent last night.
Grigg was set to start against Carlisle but suffered a shin injury in training on Monday and has undergone an X-ray to check for any bone damage.
With Grigg missing, Chris Maguire came into the side and scored twice against Carlisle.
Parkinson said: "Initially, Chris wasn't going to play - I was going to start with Griggy and Charlie [Wyke] up top, with Chris on the bench.
"But Griggy got a whack on his shin in training on Monday and we have had to send him for an X-Ray, but touch wood he will be OK and it won't be too bad.
"So we put Chris in the number ten role behind Charlie, he got his two goals and I was pleased with his contribution."
