ANAHEIM, Calif. -- Dan Haren is used to playing the No. 2 violin, to being the guy who gets the polite applause after the virtuoso finishes taking his bows.
He came up in St. Louis when Matt Morris was still an ace, moved to Oakland when Barry Zito still could dominate a game, then got traded to Arizona, where he immediately watched Brandon Webb win his first nine games on the way to 22 wins.
Now, Haren is off to one of the fastest starts of his career, and there's Jered Weaver, pitching -- arguably -- just a little bit better. Drafting seems to suit Haren, who somehow managed to start an All-Star Game and win 95 games amid the shadows of so many tall trees.
"I was thinking about that today. I've had the best years of my career when I've had someone like that with me," Haren said. "I'm pretty under-the-radar and you'd think maybe I'd get a little more publicity, but then Weaver comes out and has the year he's having, which is totally fine with me.
"I feed off him, really."
It's hard to put your finger on how these two pitchers are building this collective roll, literally pulling along the fast start to this Angels' season. They didn't know each other before last July, when the Angels acquired Haren from Arizona. Just four years ago, they were on opposite sides of a fairly heated rivalry, Anaheim versus Oakland.
Their personalities don't particularly mesh, especially on the field, where Weaver wears his emotions like a bright red jersey and Haren keeps his feelings deep in his gut.
But clearly some chemistry is propelling one of the best starts for a two-man pitching tandem in major league history. Weaver (5-0) and Haren (4-0), who pitches Friday, are the first pair of major league teammates to combine for a 9-0 record after 18 or fewer games since 1928, when two New York Yankees named Herb Pennock and George Pipgras pulled it off.
Here is a partial list of categories that either Haren or Weaver leads the league in: wins, ERA, winning percentage, WHIP, walks per nine innings, innings, strikeouts, complete games, shutouts, strikeout-to-walk ratio, ERA-plus and wins above replacement. There are others, but why go on?
Neither pitcher can pin down the dynamic at work, but clearly they're exchanging notes.
"Even when we're pitching, we'll talk to each other and see what we did with that guy or what we could have done different with that guy," Weaver said.
They have divergent methods -- Weaver has a slider and Haren has a cutter, Weaver has a changeup and Haren has a split-finger fastball -- but similar mentalities. They're not so dissimilar that it doesn't benefit each of them to watch the other's starts. They approach pitching with a similar fearlessness, often throwing off-speed pitches in fastball counts. If they walk more than two batters in a game, it's an inefficient day by their standards.
What sets them apart from run-of-the-mill right-handers, in the estimation of Angels pitching coach Mike Butcher, is an ability to locate every pitch they throw. Each has a way of deceiving a hitter's eye and disrupting a hitter's timing. Haren accomplishes it with what Butcher calls a "hitch-in-his-giddyup," that mid-delivery pause. Weaver does it by being 6-foot-7, throwing across his body and keeping the ball hidden.
Both can dominate a game without once touching 92 mph on the radar gun, but both have the ability to throw harder if they wish. Each keeps a little extra in reserve -- or, as Haren puts it, "I kind of keep it at the speed limit."
It might be enough to say they're simply in the prime of their careers. Haren is 30, Weaver 28. Neither pitcher feels as if there's a game of one-upmanship going on, even if it has often looked that way. Two days after Weaver struck out 15 Toronto Blue Jays, Haren threw a one-hitter against Cleveland.
"The whole friendly competition thing, I think people make that up," Haren said. "To be honest with you, his competitiveness on the mound inspires me. He's like a different person out there."
Weaver said having Haren here reminds him of when John Lackey was still in town, and not in the visitors dugout.
"He wants to be out there every fifth day, he wants to compete," Weaver said.
Here is what Weaver sees of himself when he watches Haren work: "He knows when to change speeds, he knows when to throw a cutter in a fastball count, he knows when to bury a pitch when he needs to. I think that's where I've come a long ways, just learning how to pitch and not just going out there and throwing everything as hard as I can."
Weaver, you might recall, began his major league career by going 9-0 in 2006. This current streak feels different. It takes him awhile, but he finds the right word: satisfying. That early success may have had more to do with the hitters' lack of familiarity than with a brilliant grasp of pitching. He was only 23 then.
"I've hit the bumps in the road and had some successful seasons and some not-so-successful ones. Just coming a long way to where I am, that's pretty satisfying," Weaver said.
This early dominance by the Angels' top two starters -- and it is, of course, early dominance -- has had some ripple effects on the staff. Consistently long outings have given the bullpen needed rest at times. They're showing the Angels' younger pitchers -- and there are a lot of them right now -- how you attack a major league lineup, then do it again five days later.
Angels manager Mike Scioscia said he's already seen 21-year-old rookie Tyler Chatwood's "ears perk up" when Weaver and Haren are talking in the dugout. Chatwood looks like he has similar moxie, if not similar maturity. He managed to pitch around the first 10 Red Sox base runners before the 11th -- Jacoby Ellsbury -- managed to drive in two runs with a broken-bat single in the sixth inning Thursday night.
Chatwood is in a pretty good place to learn while two of the most polished pitchers in the league work their craft.
"He's paying attention," Scioscia said.
Mark Saxon covers the Angels for ESPNLosAngeles.com. Follow him on Twitter.