Mike Celizic

The plan announced by Yankees general manager Brian Cashman is to start the 2008 season with Joba Chamberlain in the bullpen. That should be good news to the team’s fans. The long-range plan for the season is to move the sensational young pitcher into the starting rotation. That news might not be nearly as good.

It’s a tough call the Yankees have, one that I wouldn’t like to make. Chamberlain, Philip Hughes and Ian Kennedy are the kids whom the Yankees have groomed to form the core of the team’s rotation for the next decade or longer. And there’s no question New York needs the lift that strong, young arms can give a starting rotation.

The plan all along had been to use the 22-year-old Chamberlain as a starter, the role in which he excelled as a minor leaguer. But last year he proved to be an exceptional reliever, and in this era of ball, there’s no one more important to a team than a great closer.

The Yankees know that as well as anyone, having had the luxury since 1997 of the services of Mariano Rivera, arguably the greatest closer ever. We spend inordinate amounts of time every year talking about the mighty Yankee offense, but the reason they’ve been in the playoffs every year since 1995 is their closer, first John Wetteland and then Rivera.

Rivera got his start as Wetteland’s set-up man, and after the Yanks won the 1996 World Series, they let Wetteland go to Texas and handed the job over to Rivera. He’s done pretty well with it ever since.

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But Rivera is 38 years old, and even though the Pinstripes gave him a three-year contract in the off-season, it’s foolish to think he’ll still be the Sandman at age 41. I’ve been wrong on Rivera a lot, and I don’t think there’s been a season in the last three or four when I haven’t said his end is near. So I’m not going to make any dire predictions other than to point out the obvious: he’s getting old and won’t last forever.

What’s notable about Rivera is that the Yankees brought him up through their farm system. They’ve gone everywhere for starting pitching and position players, but Rivera has been there year in and year out. Lord knows where the team would have been if they didn’t have them and had pursued their usual course of hiring over-the-hill free agents with bloated salaries to do the job. But I’d say you can get an idea by checking out what Billy Wagner has done for the Mets — or is that to the Mets.

Last year, as Rivera’s set-up man, Chamberlain pitched 24 innings in 19 games. He gave up just 12 hits and one earned run while striking out 34; his ERA was 0.38. I submit those are better numbers than he would have had as a starter.