Brendan Rodgers reckons the "explosive" style of Moussa Dembele was a major cause in yet another hamstring injury that will see the French striker miss Celtic's Champions League second-round qualifier at home to Rosenborg on Wednesday.

Dembele, 22, scored two goals in last week's 3-0 win against Armenian club Alashkert at Parkhead as the Scottish champions completed a 6-0 aggregate victory but limped off in the second half.

"Moussa will probably be out for a couple of weeks, certainly both legs of this round," Celtic manager Rodgers told reporters on Tuesday.

"It is a minor strain. Sometimes the hamstring can be six to eight weeks but this is one that from the time it happened, we have been told two to three weeks maximum.

"It is unfortunate because he has looked very good over pre-season but he will be back fit and strong."

The former Liverpool boss added: "Maybe he has it once or twice a year. Sometimes you get that with explosive players.

"As I say, they are into the season early. He couldn't have done any more. He came back lean and fit, it is just one of those unfortunate things. But he will be back soon."

The Northern Irishman said that, ideally, clubs would not be playing fixtures as early as July.

"I feel for all the coaches up here, in terms of Champions League, Europa League and the (League) Cup games," Rodgers remarked. "Managers and players are expected to be in full flow within one or two weeks which is unrealistic really."

"I feel for all managers and players who are having to get teams out to win games when this time of the season is for fitness," added Rodgers, who also said Odsonne Edouard had overcome a knee injury ahead of the first leg against Norwegian side Rosenborg.

Celtic, the first British club to win the European Cup back in 1967, have played in the Champions League proper in the last two years but now face four qualifiers instead of three this season.

Greek club AEK Athens are waiting for Celtic if they beat Rosenborg, who recently experienced off-field turmoil when manager Kare Ingebrigtsen and his assistant Erik Hoftun were sacked last week -- a decision that led to the Rosenborg players issuing a statement saying they "vehemently disagreed" with the move.

"Obviously the manager previously had great success and it sound like he built up a real bond with the players," said Rodgers.

"For them to qualify and for him to lose his job was obviously a surprise and the support of the players and the supporters showed they maybe weren't so happy with the decision.

"However, the club has made the decision and the players and the new coach (Rini Coolen) has to move on.

"It can work one or two ways. It can either galvanise the team or it can have a negative effect.

"But our concentration is very much on ourselves to do our own job and we will look to do that over the two legs."