For Bob Welch, 5 o'clock will never come earlier than it does Tuesday.

It has been 10 years since Welch was a 21-year-old Los Angeles Dodger rookie and struck out Reggie Jackson in one of the World Series' most memorable at-bats.Now, Welch is an American Leaguer, an Oakland Athletic, and perhaps all that is standing between the Dodgers and their second World Series championship of the '80s. He will be the A's starting pitcher in Game 3 in Oakland Tuesday, and with the A's already down 2-0 in the series, he readily admitted Sunday that he has never pitched in a bigger game.

"I'm sure it will be a tense situation," he said. "That's a simple fact."

If the Dodgers know anything about their teammate of 10 seasons, they know this: In terms of excitability, he'll make Steve Sax look comatose by comparison.

"On the Sax scale of hyper, he's about a 9-plus," Dodgers catcher Mike Scioscia said.

"When he's out on the mound, he's going in a million different directions. Bobby's problem has definitely been one of keeping him under control out there. I think it's probably still the case.

"He's so talented, you had to get him to harness it. He wants to get the ball and throw it."

Obviously, Welch was something more than a loose cannon for the Dodgers. He won 115 games for the Dodgers, with a single-season high of 16 in 1982, before being traded to the A's last December in the three-way deal with the New York Mets that brought Alfredo Griffin, Jay Howell and Jesse Orosco to the Dodgers.

And with the A's this season, Welch won a career-high 17 games in 36 starts. He struck out 158 batters in 244 2-3 innings.

Still, Scioscia remembers his frequent visits to the mound to settle down Welch, with whom he remains good friends.

"It was tough for me to get serious with Bobby sometimes," Scioscia said with a laugh Sunday. "It was tough for me to look Bobby in the eye and tell him I'd kick the ... out of him."

The trade to Oakland did nothing to diminish Welch's excitability. Terry Steinbach, the A's catcher, has said that Welch tries to get two outs with one pitch. And Boston pitcher Mike Boddicker, who faced Welch in Game 3 of the American League playoffs, noted that Welch dug a hole in the mound big enough to hold a tiger.

"If you know Bobby," said Dave Duncan, the A's pitching coach, "you know he doesn't like a lot of attention. And after the trade, he had a lot of media, a lot of things written about Bobby, what he meant to the Oakland A's, what he was going to mean to the Oakland A's.

"Early on, he put a lot of pressure on himself, but gradually he settled down."

Welch is often at his most agitated early in a game, Duncan said.

"There are times he has problems, when he looks anxious to get things going and is overly aggressive," Duncan said. "Sometimes early in a game he doesn't get focused in on things that enable him to get in a good (rhythm)."