Reimer, who's 8-1-1 with a 1.69 goals-against average and .949 save percentage in his career versus Ottawa, started the first game of the season and also got the nod over Jonathan Bernier for Saturday night's game at Air Canada Centre.
"With Reims, he's played well in their building and he's played well against their hockey club," coach Randy Carlyle said. "As a coach it does have some bearing on your decision-making process, it does. It's not 100 per cent based on that, but I would tell you I'd be crazy if I didn't look at it."
Bernier, who allowed just one goal in his first game in a Leafs uniform, has never faced the Senators. Reimer explained his success against them as a mix of teammates playing well in front of him and the ease of getting up for the Ontario rivalry.
"It's just something that's worked out," Reimer said.
Things have worked out for defenceman Morgan Rielly and winger Spencer Abbott, who will make their NHL debuts Saturday night because of injuries. Mark Fraser is out three to four weeks with a knee injury, while Carlyle said Nikolai Kulemin will miss at least two weeks with a bone chip in his ankle.
The 19-year-old Rielly, who made the Leafs out of training camp but was a healthy scratch for the first two games, figured he was in for Fraser when the team did not call up another defenceman. His parents were travelling from Vancouver to Toronto on Saturday to be in attendance.
"They're pretty proud," Rielly said. "I called home last night and they were both pretty emotional about the whole thing, which was nice. It's been a pretty cool experience for them and myself."
Abbott, on the other hand, had no idea his first NHL game was on the horizon when a phone call interrupted his nap Friday afternoon. Hours earlier he practised with the AHL's Toronto Marlies while Kulemin was injured in practice when he took a puck off his foot.
Marlies coach Steve Spott delivered the good news to the 25-year-old Hamilton, Ont., native.
"It's what you dream of being a kid is you're playing in the NHL," Abbott said. "It's obviously probably one of the best moments of my life, so obviously it was pretty special."
Carlyle said Abbott was called up because the Leafs asked for the Marlies' best forward who could thrive in a top-six role. He'll at least start his NHL career on the second line with Joffrey Lupul and Nazem Kadri.
Counting either Carter Ashton or Jamie Devane, the Leafs are expected to have three rookies in the lineup for their home opener.
"We look at it as it's an opportunity," Carlyle said. "We've stated I don't know how many times that you're going to have to add young players to your lineup. Every team does it, and we're no different. ...
"Now you add them through them out-competing and earning an opportunity over some of your veterans through training camp, they earn it through sickness, through illness, they earn it through injuries. Now we're getting young players vying for an opportunity to make an impression to the big club. Simple as that."