Alexander Mogilny left the Maple Leafs on Thursday, and returned to Toronto to attend to a personal matter, The Toronto Sun reported Friday.

According to the report, it is not known when the Leafs' leading scorer would return to the team. The Leafs were in Calgary to face the Flames on Thursday night.

Mogilny was at the morning skate in preparation for Thursday's game, and was available to the media afterward. But by lunchtime, word had spread that the forward was heading back to Toronto. It is likely that Mogilny will miss the Leafs' game vs. the Canucks on Friday night in Vancouver.

"All we found out was that Alex had to leave and at the time it wasn't clear to anyone why and I'm not sure that it's clear to anyone now," Leafs president Ken Dryden told the newspaper. "It was definitely something that meant a lot to Alex and that was enough for us and that's as much as we know."

"It's a privacy issue," Team spokesperson Dave Griffiths told The Sun, adding that the Leafs are aware of Mogilny's reason.

According to the report, Dryden didn't know whether the matter involved Mogilny individually, or if it included a member of his family. Mogilny lives with his wife and children in Toronto, but it is believed he still has immediate family in Russia.

"It's a mystery," Mogilny's agent, J.P. Barry, said. "At this point, I have no idea what's going on."

Mogilny is on track to become the first player other than Mats Sundin to lead the Leafs in scoring since the 1993-94 season. He has 24 goals and 72 points in 64 games.

"It was something that clearly mattered quite a bit to Alex and he didn't feel it was something he could talk about," Dryden told the newspaper. "Since we really don't know what it is, we can't really say when he is going to be back."