PITTSBURGH – Forward Sidney Crosby has contracted the mumps and will not play against the Tampa Bay Lightning on Monday, the Pittsburgh Penguins announced Sunday.

Crosby is expected to be through the infectious period of the disease by Monday, according to Penguins team doctor Dharmesh Vyas. He will continue to be monitored daily and could return next week.

"It's a disease that's going throughout the League and you just don't know how far it can spread," Penguins general manager Jim Rutherford said. "We're watching this on a regular basis."

Sidney Crosby Center - PIT GOALS: 9 | ASST: 26 | PTS: 35

SOG: 78 | +/-: 9

During a game against Carolina Hurricanes on Nov. 28, Crosby sustained an injury to the right side of his neck. He injured a gland and underwent a CT scan, which showed the injury, Vyas said.

The Penguins medical staff tested Crosby for mumps and his results came back negative at that time, Vyas said. Crosby was placed on medications to allow for the swelling to dissipate and once he was taken off of medications, he developed swelling next to the area of his injury.

The medical staff ran a second series of tests, including further CT scans, for mumps. Vyas said that early tests showed there was no indication of an infection and the Penguins continued to monitor him closely, as well as testing all players for mumps.

"Sidney was one of the highest on the team protecting him against the virus," Vyas said. "He had immunizations as well as a booster shot as recently as less than a year ago for the Olympics. He was well protected from his antibody standpoint. He also had no symptoms, such as fever or chills or generalized body aches, but we nevertheless continued to follow him closely."

Crosby underwent another set of tests, which included sending out DNA for Polymerase chain reaction (PCR) testing, which Vyas called a "highly sophisticated test," to the Centers of Disease Control and Prevention (CDC). The Penguins held Crosby out of a game against the Calgary Flames on Friday in anticipation of the test results.

Pittsburgh discovered the test results were positive Saturday night. Crosby has been placed in isolation, Vyas said. He said the CDC recommends five days of isolation before the infectious period is completed.

"Every indication was that he was well protected against the disease," Vyas said. "We had made sure that the whole team was checked. We immunized all of the players and staff who had low titers [a test that measures the level of antibodies in a blood sample] in protection of this. That was done approximately two weeks ago just because of the outbreak of mumps in the NHL.

"We're trying to stay ahead of it."

After missing practice Thursday, Crosby participated in the morning skate Friday before the game against the Flames. He said he felt well enough to play following the skate despite facial swelling. Penguins coach Mike Johnston reiterated that Crosby was expected to play Friday during his morning press conference.

A few hours later, Rutherford announced Crosby would sit out the next two games with an undisclosed illness and that he would undergo further testing.

"We can only go by the recommendation from the medical people," Rutherford said. "We're not going to overrule them on anything and quite frankly, that decision was approved, that he could be here and his condition worsened after the skate and that's when I got the call from Dr. Vyas. I think it was like 5:00 in the afternoon and he said that he could play in the game, but there would certainly be some risk.

"At that point, we said we're not going to do that. We're not going to do it not only for our team, but for everybody around and the visiting team."

Rutherford said he was at Consol Energy Center on Friday morning, but had not seen Crosby. Vyas could not confirm whether or not Crosby was contagious during the Friday skate.

"As soon as we have some more information about it, we will notify," Vyas said. "But obviously, we will keep all these things in mind. The fact that a player has been vaccinated, but nevertheless can still contract the virus, so we'll definitely continue to maintain a high level of vigilance on this."

Crosby's DNA sample was sent to the CDC on Friday afternoon, after Pittsburgh's morning skate, Vyas said. Crosby's swelling was something that alerted the medical staff to his potential condition.

"His condition worsened from the day before," Vyas said. "As soon as we noted that, that's when we sent off additional samples. During this whole period, we've had several medical staff involved in his care … Everyone has been evaluated him for this injury, as well as potentially for any disease."

Vyas said the symptoms for mumps are fevers and chills, which Crosby does not have, as well as pain at the site of the infection, body aches, difficulty swallowing and general tiredness. Mumps often develop in each side of the face and Crosby's has developed in only his right side, Vyas said.

Mumps has affected several NHL teams this season, including the Anaheim Ducks, Minnesota Wild, New York Rangers and New Jersey Devils. The Penguins faced the Rangers in Crosby's last game before his diagnosis.

"We've been actually sterilizing our room since the mumps outbreak started in the NHL," Vyas said. "We frequently clean out the rooms and we did again yesterday. We'll do that on a regular basis."