ROGER Federer is a big basketball fan, so he’s keeping tabs on Knicks point guard Jeremy Lin and hopes they can meet.On a conference call Thursday to promote a March 5 exhibition against Andy Roddick at Madison Square Garden—home, of course, to Lin’s Knicks—16-time Grand Slam champion Federer said he’s "heard a bit about” the latest NBA phenomenon.Federer says it’s quite an "incredible story, actually, and I hope he can come to the exhibition.”He calls the Harvard player’s surprising stardom an example of "why, I think, we all follow sports—because of great stories like this,” when "all of a sudden, someone breaks through that you didn’t know or didn’t expect.”