The 32-year-old midfielder had his nose broken in Saturday's 0-0 draw against VfB Stuttgart in the Bundesliga and Dortmund will need his experience to help them improve a poor away record in Europe's elite club competition.
It was initially feared Kehl may have fractured facial bones in an aerial clash with Stuttgart's Raphael Holzhauser.
"It seems only the nose is broken," said Dortmund coach Jurgen Klopp.
The club explained on their website that it would take six hours to build a special mask to protect Kehl's nose.
Dortmund beat Real 2-1 on home soil two weeks ago and an unlikely victory for the Germans in Madrid would put them four points ahead of the Spaniards at the top of the group.
Klopp's team have seven points from three matches, with Real on six, Ajax Amsterdam on three and Manchester City on one.
Dortmund were beaten in all three of their Champions League games on the road last season. The team's last away win in the competition was at AC Milan in 2003.
The Germans have only won one European game in Spain in eight attempts, a 1-0 Champions League group stage triumph at Atletico Madrid in the 1996-97 season when they went on to lift the trophy.
Real seek an eighth straight home win since losing 2-0 to Barcelona in the 2010/11 semi-finals. They have scored 27 goals in compiling seven consecutive victories at their giant Bernabeu stadium.
LESS EFFECTIVE
Jose Mourinho's side warmed up for Tuesday's game with a 4-0 La Liga win at home to Real Zaragoza but were not at their best despite the lopsided scoreline on Saturday.
In the absence of the suspended Xabi Alonso and the injured Sami Khedira, Mourinho deployed new signings Michael Essien and Luka Modric in the central midfield holding roles and the pair were considerably less effective.
Mourinho has Alonso available again for Tuesday while Khedira, forced out of the tie in Dortmund after aggravating a leg strain, is a doubt.
"I didn't like the game much. We can and we should play better," said Mourinho after the Zaragoza game.
"The important thing is to win and do so comfortably but we must play better than we did," added the Portuguese who is bidding to win the Champions League with a third club after triumphs with Porto in 2004 and Inter Milan in 2010.
Probable teams:
Real: 1-Iker Casillas; 4-Sergio Ramos, 3-Pepe, 18-Raul Albiol, 17-Alvaro Arbeloa; 19-Luka Modric, 14-Xabi Alonso; 22-Angel di Maria, 10-Mesut Ozil, 7-Cristiano Ronaldo; 9-Karim Benzema
Dortmund: 1-Roman Weidenfeller; 26-Lukasz Piszczek, 4-Neven Subotic, 15-Mats Hummels, 29-Marcel Schmelzer; 6-Sven Bender, 8-Ilkay Gundogan or 5-Sebastian Kehl, 11-Marco Reus, 10-Mario Gotze, 19-Kevin Grosskreutz; 9-Robert Lewandowski.
Referee: Cuneyt Cakir (Turkey).
