Before trudging back to the dugout, Sexson looked for some information to use his next trip to the plate. "What the heck was that?" he asked the home-plate umpire.
"I have no idea," came the answer. "Never seen anything like it."
That's just one of the many stories you'll hear if you ask around baseball about Harden. From teammates and opponents to scouts, umpires and executives, it's virtually unanimous that Oakland's 25-year-old Canadian has everything it takes to be a superstar.
In fact, baseball people have been predicting Cy Young Awards and no-hitters for Harden since 2003, when he broke into the big leagues by going 3-0 with a 1.33 ERA in his first four starts.
At age 21, he became the youngest A's pitcher to start a game in more than 10 years, quite an accomplishment given that the team already had a trio of aces on board in the "Big Three" of Tim Hudson, Mark Mulder and Barry Zito.
Hudson was 23 when he came up in 1999, Mulder and Zito were 22 when they came up in 2000.
"[Rich has] better stuff than all three of us," Mulder said in 2004, the Big Three's last season together in Oakland. "I mean, that's the bottom line. That's just the way it is. Once he matures and gets more big-league starts, he's going to become better, and I wouldn't put it past him to be better than all three of us at some point. I mean, he could be that guy who honestly could pitch 200 innings and give up 100 hits. It's that kind of silly stat that you could see out of this guy."
Three-plus years later, though, Harden isn't any closer to superstardom. And only once, in 2004, has he come close to working 200 innings, falling 11 short.
He's flirted with no-hitters and still has the same devastating repertoire. Harden mixes high-90s heat with a plus changeup and slider, and the pitch that stymied Sexson -- a splitter that occasionally knuckles and was nicknamed a "spluckle" by A's catcher Adam Melhuse -- is one of the best pitches in the bigs when Harden's on his game.
But simply keeping Harden on the mound -- and off the disabled list -- hasn't been easy. He's never gone a full year without spending time on the DL, and over the past two seasons, he's made just 28 starts. Two DL stints in 2006 limited him to nine regular-season starts and rendered him a non-factor in Oakland's run to the American League West title.
So far, the A's have managed to make do without a healthy Harden. But with zero members of the Big Three left to provide a safety net -- Hudson and Mulder were traded after the 2004 season, and Zito signed with the Giants over the winter -- there are more than a few people hoping 2007 is the year that Harden finally takes over the "ace" role long reserved for him.
Harden, however, is more concerned with staying healthy than with feeling any extra heat related to Zito's departure. With a strong starting staff that includes another potential star, righty Dan Haren, as well as third-year righty Joe Blanton and veterans Esteban Loaiza and Joe Kennedy, Harden isn't feeling anything like Atlas.
"I wouldn't say it's added pressure," he said last week, "but I'm definitely looking forward to stepping up. I think the other guys will carry some of that load, too. Haren, Loaiza, Blanton, all these guys -- they have to step up, too."
In an effort to stay healthy, Harden is taking steps to prevent the two injuries that truncated his 2006 season.
The first injury was a strained oblique (side) muscle, not his first, and while nobody can say for sure that the strains are the result of what Beane calls Harden's tendency to be "overzealous" in the weight room, Harden is cutting back on his upper-body work.
The second injury was a strained elbow ligament, and the A's know exactly what caused it. Harden was overextending his arm upon delivering his changeup, so he's working on fixing the mechanical flaw.
"The injuries aren't even in my [thoughts] at all anymore," he said. "That's all behind me."
If it really is, and Harden reaches his goal of 200 innings this season, the baseball world's effusive praise of his stuff might finally translate to the "silly" stats of which Mulder spoke. But like the "spluckle" that left Sexson scratching his head, 200 innings out of Harden is something nobody's ever seen.
"I really hope Harden makes all his starts this year," Zito said Thursday. "I'm just as curious as anyone to see what happens if he does. It could be pretty special."
Mychael Urban is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.