Mstislav Rostropovich is the conductor of the National Symphony Orchestra.

He is tired.

So tired he could not play last night when the orchestra began its summer series at Wolf Trap, giving the free agent from Seattle, Varoujan Kodjian, his big chance.

Rostropovich is resting in Rio de Janiero for a week, on the inactive list. Some people who read the sports pages may laugh at the idea that a grown man could get tired waving a little baton.

But waving a baton is no tall Rostropovich does.

He also plays the cello.

In the last two months, hardly a day has passed without Rostropovich playing the cello or waving a baton. He's been in England, Spain and Hollywood, working the classical majors.

The Hollywood job was especially tiring. A newspaper story said, "And at the Hollywood Bowl, he played the Dvorak cello concerto . . . as well as the Brahms double concerto with violinist Itzhak Perlman. Among the concerts he conducted was an all-Tchaikovsky program similar to the one he will do at Wolf Trap, including the 1812 Overture complete with cannon."

Some people who read the sports pages may say, "Piffle, flap and doodle. The gentleman did not carry the cannon, he simply waved his baton at the gunners." Len Hauss never misses a gig.

Music lovers point out the strain of big league conduting. From Hollywood, Rostropovich went to Rio, where he did seven concerts in 10 days. The Conductor's Association has a liberal contract with the owners. But the seven concerts was the least of it.

"He went to numerous dinners in his honor (the newspaper story said), a few cocktail parties and was said to be spending his free time looking for icons, samovars and other antiques, while his wife went shopping for jewels."

If waving a baton and looking for samovars doesn't wear a guy out, his wife's shopping for jewels will.

So Rostropovich is "overheated, exhausted and suffering from low blood pressure," sounding more like Ali than Ali.

Music lovers are sending get-well cards to their hero in Rio.

Better they sent him to spring training, or Deer Lake.

Rostropovich must be out of shape and here it's three weeks after the All-Star Game.

Back in February, Rostropovich should have worked out with a weighted baton. George Shuba was a great hitter for the old Brooklyn Dodgers. They called him a "natural" hitter. In his basement, Shuba had a baseball bat made of lead. He swung it a thousand times a day all winter to become that "natural" hitter. Has Rostropovich ever waved a lead baton.?

Alas, maybe Rostropovich has lost it in his legs. He is 51, old for an icon shopper. There's all that walking around looking for samovars. Then there's standing around at cocktail parties. That's even before the tough part of waving a baton for a couple hours. Rostropovich needs to run some laps around the Tidal Basin, or Redskin Park.

Pete Rose plays third base, not the cello. While it is true he has never been shot out of a cannon, or whatever it is that Rostropovich did in 1812, Rose has suffered for his art. Other players have cut him with their spiked shoes. They have thrown baseballs at his head. Even when he performed well, audiences have booed him mightily.

Yet he plays every day and never, never asks for a week off in Rio to rest up. Some people who read the sports pages may say, "Yea, verily and when did Rostropovich last slide head first into the oboes?"

We should not be too hard on the maestro. He has fought the good battle, as we all do, and he has given us a new way out. Just as Jack Nicklaus invented a new excuse for a triple bogey in the U.S. Open - he said he went off the fairway to a portable toilet, there leaving his concentration - Rostropovich has given us an unforgettable tale of woe.

Early this season sports page readers were pleased with Claudell Washington's story. He is an outfielder with the Chicago White Sox who missed some games. He simply vanished. No one thought to look for him in Rio, which is a nice place to disappear to, with or without a cello, but Washington was back in uniform, after three days.

When somebody asked where he'd been, the outfielder said, "I overslept."

As beautiful as Washington's excuse was, it is as nothing next to Mstislav Rostropovich's samovar expedition. We all owe him a beer, for if his bosses buy that bit about icons and samovars, bosses everywhere will buy anything. Take an extra day, maestro.