Robert Lewandowski, left, is battling with a thigh injury. Photo: Matthias Schrader/AP

Celtic were handed a boost ahead of Tuesday’s Champions League match at home to Bayern Munich as the Germans’ star striker Robert Lewandowski was ruled out by injury.

The 29-year-old hot-shot injured his left thigh in the first half of Bayern’s 2-0 win over RB Leipzig on Saturday, and stayed in Munich when the squad flew to Scotland on Monday.

Lewandowski is Bayern’s top scorer this season with 13 goals.

Second-placed Bayern need a win in Glasgow to keep the pressure on Group B leaders Paris Saint-Germain, who are three points clear at the top, while Celtic are third.

Head coach Jupp Heynckes had hoped Lewandowski would be able to play at Parkhead, but took the decision to rest the Poland international ahead of Saturday’s Bundesliga clash at Borussia Dortmund.

“It’s a precautionary measure, the coach didn’t want to take any risks. He (Lewandowski) will be able to play on Saturday,” said chairman Karl-Heinz Rummenigge.

“If we were playing against Real Madrid, he might have gone, but Saturday’s game is in the back of our minds, which is very important for us.”

Heynckes will have to improvise in attack against the Scottish champions, who equalled their own 100-year-old British record at the weekend by extending their unbeaten domestic run to 62 matches.

Forwards Thomas Mueller and Franck Ribery are out with hamstring and knee injuries respectively.

Reserve striker Kwasi Okyere Wriedt is not registered for the Champions League, which means Under-19 striker Manuel Wintzheimer has been added to the squad for Glasgow.

After Lewandowski limped off before half-time on Saturday, Heynckes used Thiago Alcantara, Arturo Vidal and James Rodriguez to attack in the second half against Leipzig with limited success.

The trio failed to add to the scoreline after Rodriguez and Lewandowski had scored first-half goals.

“It’s crazy that we only have one striker,” bemoaned defender Jerome Boateng.

French winger Kingsley Coman has been declared fit after an injury layoff, but goalkeeper Manuel Neuer remains sidelined long-term with a fractured foot.

Celtic boss Brendan Rodgers has injury worries of his own.

Right winger Patrick Roberts picked up a knock in Saturday’s 1-1 draw against Kilmarnock, which rules him out against Bayern, with James Forrest set to take over.

“It looks like a hamstring, so we’ll get a scan on that. I’d suggest he’d probably be out for a few weeks,” said the Celtic boss.

“It’s unfortunate, but the squad’s there to cope.”

Striker Leigh Griffiths says Celtic will be a different side to the one which lost 3-0 in Munich a fortnight ago.

“The game will be different here, especially with the crowd getting behind us,” he said.

“In the second half at Bayern, we were much more disciplined to go and play. We created good chances to score goals.

“If we can replicate the last half-hour we played over there, then we give ourselves a good shot.

“It is going to be a difficult night for us, but as you have seen previously, big teams have been turned over when they came here.”