The Knights had five weeks to kill between their second-round elimination in the Ontario Hockey League playoffs and Friday's Cup opener against the Val-d'Or Foreurs.
It was over seven weeks for Stolarz because of an eight-game suspension for slashing a Windsor Spitfire in a first-round game March 25.
Jake Patterson finished out London's playoff run, which lasted six more games. The OHL waived the final two games of Stolarz's suspension so he could play in the Memorial Cup.
"To be honest, I just want to go out there and compete," said the 20-year-old from Jackson, N.J.
"Obviously not playing, I think it was 56 days, was a little bit of a challenge, but I think over the last three and a half weeks of practice we've competed and battled and we couldn't be any more ready for this tournament."
Stolarz backstopped the Knights to an OHL title in 2013 with a 13-4-1 post-season record. The Philadelphia Flyers prospect posted a goals-against average of 2.53 and a save percentage was .923.
But the 19-year-old Patterson, from Sault Ste. Marie, Ont., played more games for the Knights this season.
Stolarz represented the U.S. at the world junior hockey championship in January and was then sidelined for 17 games with a severe leg laceration. Patterson went 22-9-0-3 in the regular season and 2-4 in the playoffs.
Patterson's experience combined with Stolarz's lack of recent games made London's goaltending situation hazy for the Memorial Cup, until Knights coach Dale Hunter confirmed he would go with Stolarz as his No. 1 again.
"It was a tough decision, but Stolz is the guy," Hunter said. "Both of them have been very good in practice.
"Stolz has been solid for us before he got hurt, and in the playoffs. Suspension and injury put him back, but three or four weeks have honed his game up really good."
Stolarz and Patterson both have previous Memorial Cup experience. Stolarz started last year's tournament in Saskatoon, but the six-foot-six goalie appeared to tire after the long playoff run.
Patterson finished the tournament giving up one goal in a tiebreaker win over the host Blades and stopping 32 of 34 shots in a 2-1 semifinal loss to Portland.
So if Stolarz can't recover his game quickly, Patterson is waiting in the wings.
"You have to prepare for anything," Patterson said. "If Stoles were to get sick during the season or if I were to get sick and he had to start last minute, I'm sure both of us would be ready. It's kind of the same situation right now."
Hunter recruited former NHL goaltender Jeff Hackett to work with both goaltenders in their Memorial Cup preparation.
"We did a lot of game-oriented drills where we'd focus on plays that happen so often, rebounds, tips from the point," Stolarz said. "Working on things like that got us really prepared for the tournament."