BEN SHEETS' CURVEBALL IS WIDELY regarded as one of the best in baseball, a pitch that fools hitters more often than not. So the A's were initially perplexed back on May 2 when the Blue Jays swung repeatedly and aggressively at Sheets' out-pitch, attacking the ball like a pinata. Toronto mashed three extra-base hits against the curve that day, racking up nine runs in 3 1/2 innings against Sheets. And while any pitcher can have a bad outing, it was the Jays' approach at the plate that made the A's coaches suspicious. It was almost as if the hitters knew what was coming.

Another piece of information contributed to the Athletics' suspicions. Toronto manager Cito Gaston is known as one of baseball's best at recognizing when a pitcher is tipping his pitches. Players say that Gaston can detect the most subtle tells, like a great poker player reading a bluff from a minor twitch. So it wasn't a huge leap to think Gaston had noticed that Sheets was doing something every time he threw his curveball.

The effort to find these clues in pitchers is a constant enterprise in dugouts, one that has been going on since hurlers and hitters first stood upright on the diamond. As a 13-year-old in 1983, Eduardo Perez, the son of Hall of Famer Tony Perez, was sitting in the Phillies' dugout flipping seeds when Pete Rose walked over and snapped at him, "What are you doing? You need to concentrate on every pitch." The teenager moved next to Rose and listened as the eventual all-time hits leader correctly predicted pitch after pitch after pitch, because Rose had studied the mannerisms of the man on the mound. Perez, now my colleague at ESPN, was hooked by the mental challenge. In his 13 seasons as a big leaguer, he became known throughout baseball as the Babe Ruth of pitch-tipping, a master of the venerable art of recognizing how pitchers betrayed their intentions.

Perez, Gaston and others like them read key pieces of information from seemingly meaningless images or actions. For instance, with righthanded pitchers, the way the glove is splayed in the hand can be telling. If the webbing fans out as the pitcher grips the ball, that can mean a changeup is coming, because the pitcher often digs his pitching hand deep into the glove to grip the ball properly. If the webbing is not fanned out, hitters can anticipate a fastball.

Another classic tell: how far a pitcher holds the glove from his body as he begins his delivery. When some pitchers are about to throw a curveball, they have a tendency to hold the glove farther away to gain the proper wrist angle for their grip. It's similar to the way that you need room to grip a bolt with a pair of pliers.

Of course, some in the game view these divining abilities with skepticism. "If you know what's coming, why are you hitting .200?" players would often ask Perez (who batted .247 lifetime). The answer, of course, is that seeing and doing are two different things; not every hitter uses the information effectively or is capable of executing. Nationals slugger Adam Dunn remembers being told how Randy Johnson tipped his slider; in fact, many veterans say Johnson constantly tipped his pitches, but he was so good at throwing them it didn't matter. "After the fifth strikeout [in six plate appearances], I quit looking for it," Dunn says. "If it's blatant, if it's obvious, then I want to know. But if it's not blatant, I don't want to know. I'll watch during warmups and see if I can see it; if not, I'll forget about it."

Dunn does have plenty of information at his disposal, because Nationals hitting coach Rick Eckstein is also among the fraternity of those adept at picking up signs of pitch-tipping. "He's unbelievable," Dunn says. "The best. He's so good that I think he makes stuff up and talks you into seeing it."

Dunn is kidding about that, but Eckstein's attention to pitchers' details is no joke. During one game, Eckstein told Dunn that a pitcher was pushing his tongue against his front top teeth, like Michael Jordan, every time he was going to throw a curveball. No tongue, the pitch would be a fastball. "I was like, 'What are you talking about?' " Dunn says. "I have no idea how he could see that. I've got 20/10 vision, but that's like borderline X-ray vision."

While batters keying on one particular pitch can be a sign that something is up, what makes pitchers worry they're tipping is when a hitter doesn't swing at a tough pitch. "If the hitter takes a good breaking ball, a pitch they normally swing at, that makes you wonder," says Pirates hurler Ross Ohlendorf. "It could be a variety of reasons, but that's one thing you look at."

Rather than obsess over the question himself, Ohlendorf prefers to bring in quality control. At one point last season the righthander asked teammate Eric Hinske to look at video and determine whether he was tipping pitches. "If you're doing it, the adjustments are actually pretty easy," Ohlendorf says. When Perez joined the Indians in 2006, veteran righthander Paul Byrd walked over to him and asked, "Okay, what do you have on me?" In other words, Byrd wanted to know how he was tipping his pitches, and Perez told him. That's one of the main rules of a major league clubhouse: There aren't any secrets. If you share a jersey, you share whatever information you're carrying with you-hitter to hitter, hitter to pitcher.

The Yankees could've used some counterintelligence in the 2001 World Series. Before Game 6, the Diamondbacks determined that Andy Pettitte was tipping pitches when he was working from the stretch. Every time he intended to throw his curve, he would draw his hands from his shoulder level down to his waist almost in a letter C, his hands looping in front of him. But when he was about to throw a fastball, Pettitte drew his hands straight down. The Diamondbacks wrecked Pettitte, pounding him for seven hits and six runs in two-plus innings in a 15-2 win.

As a pitcher, you never can be sure when you'll have to adjust. Mets lefty Johan Santana is known to tip his changeup by the way he fans his glove; as with Randy Johnson, he's been so good that he's able to pitch around this tendency. "But as he's lost velocity, that's become more of a problem," says one advance scout, "and something he has to be cognizant of."

And that brings us back to Ben Sheets. He had thrown well in mid-April in back-to-back starts against the Orioles and Yankees. So after the Rays and Jays went 7-for-12 against his curveball in his next two starts, pummeling him for 17 runs in 7 1/2 innings, the Oakland staff decided to check out video. They wanted to determine definitively whether Sheets was tipping his curve. Sure enough, there it was: He was holding his hands in a particular manner before every curveball and in a different way before every fastball. Armed with that information, Sheets went out in his next start and limited the Rays to two runs in 6 1/2 innings in a 4-2 win. Since recognizing how much he was giving away, Sheets' ERA is 2.52 and he has struck out 29 batters in 25 innings.

It's almost as if the hitters don't know what's coming.



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