So let's let A's shortstop Bobby Crosby take at crack at this increasingly tough job.
"I haven't played behind anybody that good in my life," Crosby said after the A's beat the Giants 6-0 Saturday in a battle between Haren and Barry Zito, current and former A's aces.
Let's let that statement sink in and remember some aces Crosby has played defense behind.
There was Tim Hudson. And Mark Mulder. And Zito. And Rich Harden. Not a bad foursome.
None of them, Crosby said, pitched better than Haren has pitched this season. Now we're getting a clearer picture of just how dominant Haren has been.
"This stretch that he's on from the beginning of the year is incredible," Crosby said. "To see him paint (the corners) the way he does and the way his ball moves and making good hitters look bad, I haven't seen anything like it."
Haren held the Giants to five hits -- all singles -- over seven innings. He struck out six and didn't walk a batter. He wasn't untouchable, but he was close.
To Giants manager Bruce Bochy, Haren is probably "the hottest pitcher" in baseball.
Haren's numbers certainly help make that case.
Haren is 7-2 and has won seven straight games, a career best. He lowered his already microscopic ERA to 1.58, the best in baseball.
What we're watching is the start of what could be one of the best seasons by a starting pitcher in the pitching-rich history of the A's.
Of course there's no guarantee that Haren will continue on this ridiculously hot roll he's on. But Haren is wise enough to know that potential pitfalls lurk in a marathon baseball season. That knowledge will keep him pushing hard and keep his ego in check.
"I'm enjoying the time right now I'm having, definitely," Haren said. "I'm pitching well. I'm throwing up zeroes.
"But by no means am I getting overconfident and losing my edge. Because as soon as that happens I'll get brought back down to reality. I'm a humble person."
If Haren keeps pitching the way he did Saturday, it's going to be hard to remain humble.
Haren punished the Giants with an array of nasty mid-90s heat -- with movement --split-fingered fastballs and breaking balls. He kept the Giants off-balance, changing speeds. And he pumped strike, after strike after strike, consistently getting ahead in the count as he has done most of the season.
To date, Haren has walked just 21 batters in 97 innings while striking out 77.
"He looks great," said Zito, Haren's good friend and former A's teammate. "He's attacking the zone. He's using all his pitches and he's just showing the league what he's all about."
What Haren is all about is throwing strikes that Crosby described as "dirty."
"He's got to be right up there with some of the better guys we've faced," Giants right fielder Randy Winn said. "We faced (Brandon) Webb a couple days ago. He pitched very well against us. And Haren threw I would say just about as well as Webb did."
Arizona's Webb is only the reigning National League Cy Young Award winner. He held the Giants scoreless through seven innings of a 1-0 Arizona win Wednesday.
Contact Eric Gilmore at firstname.lastname@example.org.