Frenchman Ribery was taken off midway through the second half in their 7-0 thrashing of Hanover 96 on Saturday to conserve energy ahead of the Bavarians' first Champions League semifinal since winning the title in 2001.
"I believe he will be ready to play," Van Gaal said. "I protected him a bit because he has had some stiff muscles."
Van Gaal, who has steered the Bundesliga leaders to the German Cup final and is on track for an unprecedented treble for a German team, can also count on striker Miroslav Klose after he overcame a stomach virus that kept him out of Saturday's Bundesliga match.
Experienced midfielder Mark van Bommel and defender Holger Badstuber will not be available for the first leg on Wednesday due to a suspension.
Lyon, playing their first ever Champions League semi, had to borrow ten mini vans from their academy to travel to Munich as their flight plans were scuppered by the cloud of ash spewing out of an Icelandic volcano and drifting across Europe. They were on their way to Stuttgart on Monday, spending the night there and then driving on to Munich on Tuesday morning.
"Coach trips remind me of when I was young in Brazil," joked Brazil defender Cris, the Lyon captain. "It's difficult for everybody but we have to accept it," he said.
"We're feeling good, we're about to play our first semifinal. What we need to do is forget about the trip to focus on our match. We'll be ready."
Cameroon midfielder Jean Makoun (groin) and defenders Jean-Alain Boumsong (calf) and Mathieu Bodmer (thigh) are sidelined with injuries.
While they have no suspended players, seven could be missing for the return leg if they pick up a yellow card on Wednesday, including Cris and playmaker Miralem Pjanic.
Lyon warmed up with a tense 2-2 draw at champions Girondins Bordeaux on Saturday that left them in third place in Ligue 1, nine points behind leaders Olympique Marseille, with five matches left.
"It will be tough against Bayern," predicted Lyon coach Claude Puel. "The Germans are always dangerous in big matches and Bayern just knocked out Manchester United. They have Arjen Robben and Franck Ribery hitting for them again. We know what to expect," he said.
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