Kevin Phillips believes it will be "a massive blow" if Charlie Wyke leaves the club this summer.
The Sunderland striker is on the verge of joining Celtic according to the latest reports, and after scoring 30 goals for the Black Cats, it would leave a huge void in Lee Johnson's strike force.
Phillips has questioned the club allowing Wyke's contract to run down and believes Johnson will have a "big job" trying to replace him.
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He told Football Insider : "It is a massive blow. I have friends in the North East who watch a lot of Sunderland and they all have their own opinion about Charlie, good or bad.
“The stats do not lie though. He scored 30 goals last season and if you take those goals out of the side they would not have even been in the play-offs.
“To lose him on a free is an undoubted blow. Why did they let it happen? Was it the player or the club that let his contract run down?
“It is a huge loss because there are not many strikers out there who will come to Sunderland and score 30 goals next season. They are few and far between.
“It is not ideal for Lee Johnson. He has now got a big job trying to replace him before they start of the season.”
If Wyke is to depart the Stadium of Light this summer, the Black Cats would be in desperate need of a replacement, despite having the likes of Ross Stewart, Aiden O'Brien and Will Grigg still on the books.
The latter two are not known for their goal scoring prowess in recent seasons and Phillips has backed Johnson to give an academy graduate a shot.
Benji Kimpionka spent the second half of the season on loan at Gary Johnson's Torquay United, but has struggled to find the back of the net.
He's been touted as the next Josh Maja since he first broke through at the Academy of Light but hasn't been given a run of games and has struggled with injuries.
Nonetheless, Phillips believes he should be given a chance. He said: “I would give him an opportunity.
“I think most will be given their opportunity to impress in pre-season. Nobody will go out on loan before the season starts because Lee Johnson will want to have a good look at the youngsters.
“He will know very quick whether Kimpioka is up to the task.
“I think the time is now for Sunderland to give the youth a chance. It has not worked with experienced players like Danny Graham and Will Grigg so why not give the youngsters a chance?
“You know they will be chomping at the bit to impress. The fans will give the young players time.
“Kimpioka is a definite option and I’m sure a decision will be made on him after pre-season.”
