Celtic dropped points in the Scottish Premiership at the weekend when they only managed a 0-0 draw at Easter Road against Hibernian.
Their lead at the top of the league table remains at three points because Rangers also dropped the ball at home with a 2-2 draw against Motherwell.
Celtic are missing key players such as Kyogo Furuhashi, but Provan feels his former side are struggling at the moment and are lacking a spark on the pitch as well.
The former Bhoy is not keen to blame Ange Postecoglou for overworking the players in training but stressed that the Scottish giants have been looking a bit tired in recent games.
Provan is keen to see the Celtic manager find a way to reenergise his side for the close title race in the coming months.
The former Celtic star said on the Go Radio Football Show: “I think he might be slightly concerned with his team at the moment.
“They have lost something.
“They don’t look the same side at the moment that they were when they took care of Rangers a few weeks ago.
“I don’t know whether it’s energy, I don’t know whether it’s overtraining.
“I am not going to accuse Ange Postecoglou of overdoing the training because I am not privy to what they do.
“But they look a bit leggy to me, and they were certainly missing Kyogo and Giakoumakis at the weekend.
“Celtic are not quite at it at the moment and they have got to rediscover their form that got them in the lead in the first place.”
Celtic will look to get back to winning ways when they host St. Mirren at Parkhead on Wednesday night.
