The Scottish champions are ready to consider a bid for former Tottenham and England defender Caulker after manager Brendan Rodgers confirmed earlier this week he had spoken to the 25-year-old who has been deeply troubled by alcohol and gambling problems.
Rodgers was initially responding on a personal basis to what he described as a “cry for help” from Caulker, but has not ruled out the possibility of signing a player who previously flourished under his management when on loan at Swansea City six years ago.
Caulker was a team-mate of Sinclair during that season and also played alongside the Celtic winger when they were both members of the Team GB squad at the London 2012 Olympic Games.
Sinclair’s own move to Celtic has been an unqualified success as he swept the board in the individual Player of the Year awards during his first season at the club and helped them secure their undefeated domestic treble.
The 28-year-old former Chelsea, Manchester City and Aston Villa man believes Caulker could find similar fulfilment on and off the pitch if he moved to Glasgow.
“There is no better place to be at than Celtic,” said Sinclair. “If he ever spoke to me, I’d tell him it’s the best place to be. It would be a great place for him to be as well. I’m sure he looks at myself and can see my career was also at a crossroads before I came to Celtic.
“When you go out on loan so many times, you’re not settled as a player. I had that experience myself, going from club to club and not really settling in. So I don’t think there would be a better place for Caulks to get back on track and start enjoying his football again.
“It’s about whether you still want it. I was out of the game for two and a bit years, really, not playing regularly or being settled. So much has changed for me in the last year since I came to Celtic.”
Sinclair scored Celtic’s first competitive goal of the new season in Friday’s 2-0 win against Linfield at Windsor Park in the first leg of their Champions League second qualifying round tie. It was a comfortable and satisfactory outcome for Rodgers’ side on an evening sullied by the missile-throwing incidents from among the home support. While Celtic were largely untroubled on the pitch, however, there were a couple of shaky moments at the back for Erik Sviatchenko which perhaps underlined Rodgers’ need to bolster an area of his team weakened by the absence of Dedryck Boyata who is sidelined for three months with a knee injury.
Caulker, who has a year remaining on his contract at current club QPR, would appear to tick plenty of boxes from a football perspective.
“He would be a great signing for us,” added Sinclair. “The manager knows him well from being at Swansea. He had an amazing season there and hopefully he can get his career back on track. He was terrific that year on loan at Swansea.
“Once your head is right and you’re enjoying your football, there are a lot of players who perform when they’re like that. It would be amazing for Caulks to sign here. The manager is definitely the type of guy who can help him. Caulks still cares and I think he still wants to be playing football.”
Assuming Celtic complete the job against Linfield in Wednesday night’s second leg in Glasgow, they will face Dundalk or Rosenborg in the third qualifying round of the Champions League. Sinclair is seeking improvement on the performance level delivered in Belfast.
“To be honest it was quite disappointing,” he said. “We didn’t play as well as a team. There should have been more goals but it was our first game and we won it so it’s a positive note going into the home game.
“Now we need to make sure we get a win there as well. To get into the group stage is what everyone is fighting for.
“I don’t think Linfield caused us too many problems. It was a game that was one-sided where we controlled it from start to finish. But I think it tested us and we need to keep the tempo up when we control games and need to finish them off. The aim was to break them down but sometimes they ended up as a back six or seven.”
Sinclair echoed the sense of dismay in the Celtic camp over the incidents in which bottles and coins were thrown at Windsor Park with Leigh Griffiths astonishingly booked for picking up one of the projectiles as he prepared to take a corner.
“Everyone was scratching their heads over why he got a yellow card,” said Sinclair “It was disappointing he got bottles thrown at him. But it happens, you get on with it and carry on with the game.”