Rangers hero Kris Boyd believes Celtic stalwart Callum McGregor could be tempted to call time on his Parkhead career this summer.

The Hoops' stand-skipper is widely regarded as one the club's best players and has been a key man during their wildly successful quadruple Treble run.

But Boyd is adamant every player among the current Celtic squad could leave apart from rising star David Turnbull.

The 22-year-old has been a bright spark amid a dreary season and the playmaker has emerged as a key man in recent months.

Embattled Neil Lennon faces an uncertain future amid his ongoing review and serious questions hang over a number of his stars,

Celtic trail Rangers by 20 points and the pundit believes Parkhead decision makers will answer every call related to the playing squad unless it's in relation to the former Motherwell man.

Speaking on the Sky Sports Scottish Football Podcast, he said: "Looking at the Celtic squad right now and we all know the financial muscle that Celtic have got.

"But when you look into their squad - I don't think any of the goalkeepers are up to it.

"You then look at the defensive, we have already been over this, you feel like your repeating yourself but there are so many of them there who will probably move on.

"You could have looked at it for a number of years and said you could build a team around certain individuals, as it stands right now, I'm probably looking at only David Turnbull who you could guarantee who is going to be part of Celtic's long-term future.

"Even people like Callum McGregor, he might say 'I've done all I'm going to do in Scottish football, I want to go on and test myself in Scottish football against the best'.

"Ryan Christie as well, I would imagine Scott Brown is not getting any younger and when you look at those guys they would have been the ones you are going to build a team around and you can bring in five or six.

"But for me, Celtic are going to need 10-plus and when you go through the whole process and structure with what is going on at Celtic at the moment in time, when you see the money that has been wasted on transfers already, and then you're saying go and recruit 10, 12 players, I don't know if I would trust anyone to go and spend the money.

"I think Celtic are in a very, very, difficult situation right now. It's all well having the money there but when you've gone and spent it on players who have not shown they are up to it, I include Klimala and Ajeti in that, it's not been good enough.

"Barkas, ÂŁ5m, there's a few loans in there as well, we've already heard Kris Ajer, there's lots of things going on within that Celtic squad where I feel, looking at it right now, David Turnbull is the only one you can probably hang your hat on that is absolutely guaranteed to be there for pre-season.

"I think everyone else, if somebody comes in, there will be negotiations to take place and you can't blame McGregor, Christie, even Ajer for saying I've done this."