Former Leinster wing Rob Russell is set to feature for Munster against Connacht on Friday evening, taking the place of Shane Daly who remains out through injury.
The selection also sees centre Gordon Wood make his debut in provincial competition this season.
James Hume and Rob Herring are confirmed in Ulster's starting XV when they host the Stormers on Saturday, marking their first action since the conclusion of last campaign after recovering from setbacks.
Ulster captain McCann leads a squad that has already undergone seven alterations ahead of the United Rugby Championship fixture in Cape Town scheduled for Saturday afternoon.
Richie Murphy's side seeks to secure their inaugural league victory of the campaign following two defeats and two draws in their opening four fixtures.
Eight players who participated in last week's loss to the Bulls are unavailable for the trip to South Africa, with Robert Baloucoune also excluded from the matchday roster.
Four individuals featured in recent Nations Championship internationals have already departed for their own international camp under Andy Farrell's management.
Leinster travel to Dublin on Friday night at 19:45 GMT after defeating Munster in a previous encounter, with experienced wing Jordan Larmour returning to the number 11 jersey following his recovery.
Connor Fahy is named in Leinster's starting line-up for their provincial fixture, while centre Gordon Wood features for Munster alongside former Leinster winger Rob Russell.
The Stormers are scheduled to play Ulster on Saturday at 17:30 GMT with the game taking place in South Africa.