Marner has been out since suffering a high-ankle sprain in a 4-3 shootout loss on November 9 against visiting Philadelphia. Wednesday marked the first day he was eligible to be activated off of LTIR.
Judging by practice lines, Marner also appears to have bumped Morgan Rielly to the second power-play unit.
Shore was placed on waivers by Toronto, after playing 21 games with the Leafs this season and recording two goals and a single assist.
Wednesday's game will be his first under new head coach Sheldon Keefe, who took over from the fired Mike Babcock on November 20.
Marincin was recalled from the Marlies earlier this week, but has not appeared in a game with the Leafs since November 2. Marincin is no stranger to being shuttled back and forth from the Marlies and has gone pointless in his seven National Hockey League contests on the year. Toronto opened the season with Hyman and Travis Dermott on injured reserve and lost Tavares to a finger injury for two weeks earlier in the campaign.