Chris Sutton is ‘concerned’ about the lack of signings at Celtic so far this summer as he looks for the Scottish Champions to strengthen when they are ‘on top.’

Kieran Tierney is the only new addition so far with the defender returning from Arsenal on a five-year deal after he agreed a pre-contract in February.

The Hoops have agreed terms with Nordsjaelland winger Benjamin Nygren with the clubs now thought to be negotiating a fee for a potential deal.

Celtic are in talks to sign Albirex Niigata centre-back Hayato Inamura, and Sky Sports News understands the 23-year-old is keen on a move to Glasgow.

Greg Taylor is out of contract with the right-back yet to decide on his future while some of Celtic’s squad are sure to be attracting interest from other clubs.

Sutton, who spent five-and-a-half years at Parkhead, hopes they do not become complacent.

“I’m a little bit concerned Celtic don’t have more players in. When a team is as strong as they have been, it’s important they add to the squad and freshen things up,” he told Sky Sports News.

“I’m sure there will be a couple more moves in the pipeline and players brought in.

“I’d always like to see them strengthen early. Then you can bed players in, there’s Champions League qualifiers for Rangers and Celtic which have such an impact on their seasons financially.

“As much as Celtic have been dominant, and won a double last season, the pressure is on right from the off.

“If Celtic had kept Kyogo, I believe they would have run away with the treble this season.

“I mean, that’s slightly hypothetical to say that because nobody knows, but they lost that quality when they sold him in January.

“People will say, well, he went over to Rennes and didn’t do particularly well there. That wasn’t the point, he scored big goals. He decided big games and he had something which other players didn’t have.

“They should have replaced him in January. They didn’t and I think that’s an area of concern.

“I think Kieran Tierney coming back is massive. He’s gone back to Celtic, arguably sort of in his peak, albeit didn’t play enough football at Arsenal. But that left-back area, the Greg Taylor thing and replacing him, it looks like he is on his way.

“Replacing him [Taylor] looks like to be a pretty big deal because he was an outstanding player for Celtic.

“Keeping hold of Cameron Carter-Vickers is a big deal for Celtic as well.

“It’s so important to strengthen when you’re on top and go again and Celtic should be trying to absolutely bury Rangers in the transfer market this season.

Sky Sports to show 215 live PL games from next season

From next season, Sky Sports’ Premier League coverage will increase from 128 matches to at least 215 games exclusively live.

And 80 per cent of all televised Premier League games next season are on Sky Sports