Crosby worked out Wednesday for the first time after missing three games over the weekend. He could return to the lineup as early as Thursday night when the Penguins face Colorado.
General manager Jim Rutherford said Crosby is "doing well," and he'll let Crosby and coach Mike Johnston decide the timetable for a possible return.
All three players tested negative for mumps earlier in December.
"We're being cautious," Rutherford said. "All three of those players are in isolation. Any time that anybody even starts to not feel well, even if it's not mumps-like symptoms, we've gotten the person or player out of here as soon as we can."
Bennett was tested Monday and placed in isolation after showing symptoms of the disease, Rutherford said. The team confirmed the diagnosis Tuesday after a series of tests.
At least five NHL teams have been affected by the virus, which is spread through infected saliva and causes facial swelling and fatigue. There's no specific treatment for the mumps, which must run its course. Most children and adults recover within about two weeks.
On Sunday, the Penguins said Crosby had the mumps and held him out of games over the weekend as a precaution when swelling developed on the right side of his face. Initially, the team believed it was related to a salivary gland injury Crosby sustained during a game against Carolina on Nov. 29.
The club is recommending employees and members of the support staff receive booster shots.
In light of the mumps situation, the league sent out a memo in conjunction with the NHL's Infection Control Subcommittee last month to provide clubs' medical personnel and trainers with recommended guidelines and protocols to assist in both the treatment and prevention of the disease.
Dr. Greg Wallace, a lead epidemiologist at the Centers for Disease Control and Prevention in Atlanta, told ESPN.com that considering mumps' lengthy incubation period, it's virtually impossible to predict how long this outbreak will affect the league.
The Associated Press contributed to this report.