With Roger Clemens, you hold your breath.

Will he strike out 20 men, as he did against Seattle in April to set a major league record for a nine-inning game? His lucky number, which he wears around his neck, is 21, so you figure he has something planned.

Will he pitch a no-hitter, as he came within four outs of doing a dozen days ago in his home state of Texas? Since the 23-year-old has allowed only 57 hits in 82 innings this year, way below the legal limit for a Boston Red Sox pitcher, he sure has a chance.

With his 9-0 start, and the hottest Red Sox team in generations behind him, when will he lose a game? Or will he? A man who is 6 feet 4, weighs 210 pounds, throws 98 miles per hour and has a brain-freezing curveball and superb control is the sort whose mystique precedes him.

Gorman Thomas, a former home run champ, calls him "overbearing." Which, if you're a hitter, is probably about right. Reggie Jackson says that as long as Clemens keeps his fastball above the belt, "I could stand up there until I collect my pension and I'd be just another notch on his gun."

Clemens could be the American League's 100-cents-on-the-dollar answer to Dwight Gooden. He could be the Fenway Messiah -- often sighted but never confirmed -- who has been sent to finish the job that Jim Lonborg began in 1967 but never completed because of a ski injury.

The Red Sox have had only two trips to the World Series in 40 years. And no world titles since 1918. Clemens could be the man -- the Tom Seaver, Sandy Koufax, Bob Gibson, Jim Palmer, Catfish Hunter -- around whom a perennial contender and an occasional world champ can be built.

"Baseball's the first sport in this town, and people are starting to get excited," said Clemens, knowing that the Red Sox' 36-16 spring into first place means more to many a Bostonian than the Patriots in the Super Bowl or another banner for the Celtics.

But with Clemens, you still hold your breath. He is, you see, the perfect Red Sox phenom -- touched now and perhaps forever -- with that hint of potential disappointment that clings around Fenway like some perverse melancholy Puritan foreboding.

Clemens has arm trouble.

A season-ending forearm injury in 1984, season-ending shoulder surgery in 1985 and, at the moment, a recurrent cracked knuckle on the middle finger of his pitching hand. He has never pitched more than 180 innings in a season. And only once in his three previous pro years has he made it to 100. His gears and levels may be too powerful for his axles. Despite a wonderful compact pitching motion that ought to be the perfect mitigation against such glitches, Clemens always seems a pitch away from losing a wheel at high speed.

"I hope all that's behind me now," he said yesterday. Others hope so, too.

As a rookie, Clemens fanned 15 in a game, tying the career best of Smokey Joe Wood, who was the Roger Clemens of 1911. At age 22, Wood was 34-5 and the equal of Walter Johnson. When Wood was 23 (Clemens' age), his arm was dead -- and with it the Red Sox' dynasty dreams died, too.

"I met him a couple years ago. Nice old man in a wheelchair. I really care for a man like that," said Clemens. "I did all the listening . . . how he said it wasn't for the money that he played, but the game. When he died, I saw an hour-long TV program on him. It was neat to meet him. Really glad I did."

Also, Clemens broke the team rookie strikeout record held by Ken Brett. The same Brett who was thought far better as a prospect than his brother George. Ken Brett was 10-15 in his Red Sox career. George Brett will go to the Hall of Fame as a Royal.

Now Clemens is on the verge of two more Red Sox records. Roger Moret once began a season 11-0, as a starter and out of the bullpen. The Red Sox also will have you know the record Clemens is really after is the fastest start to a season by a full-time Boston starting pitcher.

That's Boo Ferriss, who was 10-0 in 1946. The same Ferriss who began his Boston career 21-10, then 25-6, and won only 19 more the rest of his life.

Clemens could also be the first Red Sox 20-game winner since Dennis Eckersley at age 23. Eckersley had arm miseries and was mediocre at 25. Or Clemens could be the Red Sox' first Cy Young winner since Lonborg . . .

Whatever Clemens does, he has the double problem of meeting the team ghosts, the Red Sox' long tradition of promising star pitchers who seemed blighted, perhaps by The Wall, but also, maybe, by the city's long-ingrained habit of talking in terms of "What Will Go Wrong Now?"

Clemens knows it. How can he miss it? Until two weeks ago, Boston had its best pitching rotation since Carl Mays, Joe Bush, the original Sad Sam Jones and a lefthander named Babe Ruth. The new incarnation was Clemens, Bruce Hurst, Oil Can Boyd and Al Nipper.

So, what happens? Nipper is spiked at the plate so badly that he'll be out two months. Hurst, who has discovered a split-finger strikeout pitch and can almost match Clemens stat for stat, has a pulled groin muscle and is out of the rotation.

As a result, the weight falls to Clemens, who said: "I try to keep the minor injuries in the closet. . . . I have to play with these injuries." Last Sunday, he played hurt and went eight tough innings for a win, despite the sore finger.

Nine months after arthroscopic surgery to remove cartilage from his shoulder, Clemens is trying to carry the Red Sox -- and their modest defense and bullpen -- to a pennant. Have the Red Sox, so often burned by pushing prospects too hard, finally learned their lesson?

Yes. But does it help them? No.

"Oh, they're always tellin' me I work too hard, Fish and them," said Clemens of pitching coach Bill Fischer. "I go full speed ahead. They've been trying to slow me down, but that's how I get things done."

So, Friday, despite the sniffles and that bad finger, Clemens is back to taking his regular turn

Born and raised in Dayton, Ohio, and sent to high school in Houston, Clemens was an all-America twice at the University of Texas. He is a hard-working, broad-shouldered, already married and settled-down fellow who does little bragging or fast living.

"Everybody leaves me alone. I'm not someone you'd look to find fault with. I do my work and go about my business. If I'm sore, or start thinking too much, I go run three miles."

When Clemens sets a record, he "thanks the man in the sky," and when his teammates don't score for him, he just says, "Our pitching will persevere until our bats come alive."

Roger Clemens just wants to be a great ballplayer and help the Red Sox and their fans forget everything bad that has happened since World War I.

For Clemens, you hold your breath.