Rittich joined the Maple Leafs at the morning skate after arriving in Toronto with the Flames. The Maple Leafs acquired Rittich on Sunday for a third-round pick in 2022.
The 28-year-old has been a regular in Calgary's lineup for the past four seasons, splitting time with Mike Smith, Cam Talbot and Jacob Markstrom during his tenure. This season, he has a 4-7-1 record in 15 games, 12 of them starts, with a .904 save percentage and 2.90 goals-against average.
Jack Campbell, who played in Monday's loss to the Montreal Canadiens, will back up Rittich Tuesday.
You can watch the game in the Maple Leafs region on Sportsnet Ontario and in the Flames region on Sportsnet West beginning at 7:30 p.m. ET/ 4:30 p.m. PT.