Gagner has yet to play a game this season after breaking his jaw during the preseason, courtesy of the stick of Vancouver Canucks wing Zack Kassian. Gagner needed surgery to repair the damage done after Kassian's stick caught the Oilers center in the face.
Kassian received a five-game suspension for the Sept. 21 incident, while Gagner missed the first 13 games of the regular season.
"It's exciting to get back playing, I think the biggest thing for me is keeping the emotions in check and going out playing a simple, hard game," Gagner said. "I'm excited to be back."
"Sam's been gnawing at the bone wanting to get back in, he had to wait for the doctor's clearance to get back in," Oilers coach Dallas Eakins said. "We've got that now. We've had him right there as one of our top-two centers and we've obviously really missed that from the start of the season.
"He's a guy that brings leadership, character, he brings a work ethic and he brings some veteran savvy as well, he's been around the block a little bit. We need this guy and we need him every night. I'm just hopeful that he's up to speed very quickly."
Richard Bachman will get the start in goal for the Oilers, coming off a 47-save performance against the Los Angeles Kings on Sunday. Bachman was called up from Oklahoma City Saturday night after Devan Dubnyk awoke with a sore ankle.
Bachman was signed as a free agent this summer from the Dallas Stars and has 33 games of NHL experience.
"I thought he played a hell of a game in L.A.," Eakins said. "The great thing I liked about his game in L.A., as many pucks that he saw, it wasn't as though he was diving all over the net to make the saves. He made them look very, very easy. That shows you that he's in position, he's calm, he's collected."
Lupul, meanwhile, is hoping to be able to suit up for the Maple Leafs, having missed the previous two games with a foot injury. He took a puck in the foot against the Anaheim Ducks a week ago, but did take the morning skate with the club Tuesday.
Having grown up in Edmonton and played a season with his hometown team, Lupul is anxious to get into the lineup against the Oilers, particularly since he purchased 20 tickets for family and friends.
"He will skate in warm-up," Maple Leafs head coach Randy Carlyle said. "If he feels he's not ready to go after warm-up, then he won't. I can't tell you that he is or isn't right now."
Here's a look at the way the two teams are expected to line up Tuesday.
Scratched: Denis Grebeshkov