Turns out Blue Jackets rookie Steve Mason is battling more than just a heavy workload.

General manager Scott Howson confirmed late last night to The Dispatch that Mason has been suffering from mononucleosis for three to four weeks.

The rookie-of-the-year candidate made his 18th consecutive start last night but allowed three goals in the first 11 minutes of a 7-3 loss to the Dallas Stars and was pulled for the first time in his NHL career.

Howson said doctors did not diagnose Mason's infection until Thursday, and he defended the team's decision to play him in back-to-back starts this weekend.

"Our doctors feel he's had it for a while and they feel he's on the other side of the virus," Howson said. "The worst of it is probably over."

Mason's spleen is not enlarged, one of the complications sometimes associated with mono, Howson said.

The goaltender posted his NHL-leading seventh shutout on Friday in a 1-0 win over Ottawa. He entered last night's game with a league-best 1.98 goals-against average.

"It's up to him" (whether he can play), Howson said.

The Jackets already are without Pascal Leclaire, who started the season as the No. 1 goalie. Leclaire had season-ending ankle surgery.

Mason, 20, has been the Jackets' most valuable player with a 19-12-2 record, playing through fatigue and back spasms in an effort to keep the team in the playoff race.

He opted to skip last weekend's YoungStars Game in Montreal.

"He has been feeling run down for three weeks," Howson said. "He needs to get lots of rest and we must monitor his diet and see what his energy level is like. If he feels he cannot do it, we will make alternative plans."

The Jackets have not announced who will start Tuesday against St. Louis. Only Dallas goalie Marty Turco has a longer streak of consecutive starts (19).

After the game, Mason declined to comment when asked whether he was sick.

"We were not good from the goaltender out," said Mason, who surrendered three goals on eight shots. "This is a real wake-up call for me."

Howson said Mason will not address questions regarding the virus.

Backup goaltender Wade Dubielewicz allowed four goals on 23 shots. It was his Jackets debut and first game since playing for Kazan Ak-Bars in the Russian Continental Hockey League in late December.

Dubielewicz struggled in controlling rebounds, which led to two Dallas goals.

"This is part of the job description, (coming into a game)," he said. "I've got to be better than that. I've usually had success going into games like that. My rebound control was terrible and that's just unacceptable."

Position change?

Hitchcock said he will evaluate whether to keep converted winger Jason Chimera at center. In his third game at the new position, Chimera was minus-3 last night. His line, with R.J. Umberger and Fredrik Modin on the wings, generated little offensively.

Slap shots

Dallas rookie forward James Neal has four goals in three games against the Jackets this season. Captain Rick Nash said he wasn't sure whether Dallas agitator Steve Ott intentionally stuck a knee out during a first-period collision. Nash, who missed time because of a sprained knee, was fine and did not miss a shift. Ott was assessed a roughing and tripping penalty on the play.

treed@dispatch.com