Lewandowski, 29, limped off on the stroke of half-time with a hamstring strain, having just scored the second goal in Bayern's 2-0 victory over Leipzig at the weekend.

Bayern's top scorer underwent a fitness test in Munich on Monday and did not fly with the Bayern squad to the Scottish capital for the meeting with the Scottish champions.

However, Karl-Heinz Rummenigge suggested at Munich airport on Monday that Lewandowski would probably have played if it were Real Madrid and not Celtic as opposition.

Responding to his CEO's comments, Jupp Heynckes said at his news conference: "Karl-Heinz Rummenigge has his opinion but I always protect my players when they are not 100 percent.

"It would be pointless for [Lewandowski] to play tomorrow because then he would most likely incur another muscle injury."

Bundesliga leaders Bayern face Borussia Dortmund on Saturday, having deposed BVB from the top of the table after three straight wins under Heynckes, who was confident that the Poland captain would be fit after some rest.

"It's a precaution," he said. "He did some recovery work today and I expect him to be able to play on Saturday, but tomorrow would be too early."

Robert Lewandowski saw several chances go begging in Bayern's stunning loss to Borussia Dortmund. Christian Bruna/EPA

Thomas Muller is also out injured, leaving Bayern's resources stretched in attack, but Heynckes hoped "we will find a solution."

He added: "Of course, it's an unexpected situation with Muller and Lewandowski out injured. We can either play 4-4-2 with [Arjen] Robben and [Kingsley] Coman up front or with both of them on the wing and a midfielder as a withdrawn striker.

Bayern are second in the group behind Paris Saint-Germain, having been humbled 3-0 by Neymar and co in their previous away game in the competition, which prompted Carlo Ancelotti's dismissal the following day.

"It's obvious that all the big teams in the Champions League have a preference in attack. Barcelona with Suarez, Real [Madrid] with Benzema, PSG with Cavani. But tomorrow is different for us; we have to find another solution."

Although the prospect of playing in Scotland excites the Heynckes, he warned: "I don't have great memories against Scottish sides; we always lost by a wide margin."

The vastly experienced 72-year-old played for Borussia Monchengladbach in Glasgow against Rangers and coached against Aberdeen and Dundee United in European competition.

"It was always a great footballing experience in Scotland," he said. "It is honest football with players that give their all. They have fantastic support with great fans in a marvellous stadium. But we at Bayern are used to playing in front of such a following."