Zajac and Lovejoy were injured during a 5-3 loss to the Colorado Avalanche at Prudential Center on Thursday. Each is day to day, according to coach John Hynes, and will be re-evaluated next week.
Blake Coleman replaced Zajac at center on a line with left wing Marcus Johansson and right wing Drew Stafford, and defenseman Steven Santini replaced Lovejoy in a pair with Will Butcher during practice Friday.
Goalie Cory Schneider was activated off the injured/non-roster list and was assigned to Binghamton of the American Hockey League on a conditioning loan. He will play against Cleveland in Binghamton, New York, on Saturday.
The 32-year-old goaltender has been practicing and working out with goalie coach Roland Melanson as part of his rehabilitation program after having surgery May 1 to repair torn cartilage in his left hip.
"We want to see him get through a game, see how he responds to 60 minutes while working in more read-and-react situations than just practice," Hynes said. "It's important for him to play a live-game situation against another opponent where the score of the game matters. We're excited for him. It's a good opportunity for him to get back in and get his game back."
Zajac, 33, has four points (two goals, two assists) in five games and has won 62.8 percent of his face-offs, third in the NHL among players with at least 80 face-offs.
Lovejoy, 34, has one assist and is plus-5 in five games, and is averaging 15:49 of ice time.
