Campbell last played on March 8, when he made 26 saves in a 6-4 win against the Seattle Kraken.
"All I can say is since he's been back on the ice, he's worked incredibly hard, which we've come to expect from Jack, but I think he's just looked good," coach Sheldon Keefe said. "He's battled to keep the puck out of the net (in practice) and he just looks like he's refreshed. I think that's natural when you separate yourself from the game for a little while, so obviously we were wishing he remained healthy, but there are some positives that come with being able to take some time away. It's a long season, especially for a guy who plays that position, to get that mental and physical break, I think there's benefits to come from that."
Campbell said the injury occurred in a 4-3 overtime loss to the Columbus Blue Jackets on Feb. 22. He went on to make three more starts before missing time, allowing 14 goals on 83 shots.
Campbell has allowed at least four goals in nine of his past 15 starts.
"I've had worse, so I'm not going to make any excuse on my performance, but it's not fun to play through some pain, but it's part of the game," Campbell said Friday. "I'm fortunate the team has my back, let me heal and get stronger, and I'm just ready to go now."
The Maple Leafs were 6-3-1 without Campbell.
"I'm feeling great," Campbell said. "When coach puts me in, I'll be ready to go. It's good to be back healthy, the boys have been playing great, [Erik Kallgren] has been holding down the fort in the net. I'm just excited to get back out there."
Goalie Petr Mrazek, who went 2-1-0 in five appearances while Campbell was injured, sustained his third groin injury this season against the Boston Bruins on Tuesday and will miss a minimum of six weeks.
Kallgren (4-2-1, 2.71 goals-against average, .906 save percentage) backed up Campbell against the Flyers (7 p.m. ET; CBC, SNO, SNP, NBCSP, ESPN+, NHL LIVE).
"We both have had our own schedules right now, but we have texted a little bit and I feel for [Mrazek]," Campbell said. "I went through it last year, and earlier in the year he went through it, so he's been there but he's got a great attitude and he's going to work hard. We've got an amazing medical staff, so they'll be helping him out."
The Maple Leafs (43-19-5), who are one point behind the Tampa Bay Lightning for second in the Atlantic Division, tried to extend their winning streak to four games on Saturday in the first of a four-game road trip that will also include games against the Lightning (Monday), Florida Panthers (Tuesday) and Dallas Stars (Thursday).
Campbell (24-9-4, 2.65 GAA, .914 save percentage) said he is excited to rejoin the lineup in the midst of the Stanley Cup Playoff race.
"It's the most fun part of the year, but the whole year has been fun," Campbell said. "We're looking forward to it, the team has been playing great, so I just want to go in there and do my job.
"It's going to be fun hockey. We're going to be competing with the best teams, and obviously we're just focused on being our best today and that's about it. Tomorrow we'll go out there and give it our best, and we're focused on the present moment, and I'm pretty confident if we do that, we'll be right where we want to be."
