CELTIC hero Frank McAvennie has branded James McCarthy's injury struggles as a "big problem".

The former Hoops striker reckons Ange Postecoglou has issues when the midfielder is out injured as he's a unique player at Parkhead.

McCarthy has endured a stop-start beginning to life at Celtic and has not featured in the last two matches through a muscular injury.

McAvennie has now called on Postecoglou to be careful with McCarthy as he claimed the Irishman is "not fit enough".

McAvennie told Football Insider: "He’s a big problem. He is the one Celtic wanted to come in and sit in the middle. That’s an important part of that side.

“It’s not happening because he’s not fit enough. He’s getting more injuries because he’s not fit enough when he does play.

“I don’t know what the situation is, I like him. Turnbull and Rogic are great going forward.

“So we need someone to sit in the midfield and win tackles. That’s what he’s for and he is a good player.

“I don’t think there is anyone else at Celtic who can do that, so we need to be careful with him.”

Postecoglou revealed McCarthy could return to action against St Johnstone this weekend as he assured fans the midfielder is close to a comeback.

He said: “James had a good 10-day block during the international break so this is just a minor setback for him, nothing significant. We’re just erring on the side of caution.

“He trained [on Monday], but on his own. We didn’t want to rush him back so we’ll see how it goes by the end of the week. It’s just a small muscular problem, so we’re hoping he’ll be available [for St Johnstone].”