"I learned this craft in 2001, my second year in pro ball. I've been using it ever since," Shields said. "I feel like identifying leads at first base is a big part of my game ever since and it's kind of evolved into more of a recognition thing rather than trying to get any better. I've always had quick feet, I just never realized what was going on over there."
A key element for Shields is recognizing how big of a lead a runner is taking. This he does by measuring the "cutout" into the grass that each field has in front of first base. The length varies from ballpark to ballpark so he makes it his business to know the difference.
If you watch Shields, he has an unusual stretch motion that begins with a "dip" during which he gets a good view of the runner at first base. His pitching pal who also came over from Tampa Bay, Wade Davis, also uses it.
"We do it because you can't identify a lead with your peripheral vision," Shields said. "You come set and your peripheral vision only measures movement, it doesn't measure distance. So when we do that, we look with both of our eyes. So when we look with both our eyes, we can judge and measure the distance on where they're at. So when we come set, if we see movement and they take one step to their right, we know what kind of a lead they have before we come set. So if they take one step to the right, we know they've got a bigger step. If they're one step to the left, we know exactly how far they are."
Shields developed his move with the help of Minor League coach Dick Bosman.
It's not necessarily how many runners are actually picked off, it's that they know the move is there and could be used. So they're more cautious, take shorter leads and are less likely to try a stolen base.
Since Shields came on the scene in '06, left-hander Mark Buehrle is the pickoff leader with 56 runners nailed. Shields is tied for fifth in that span with teammate Bruce Chen and Atlanta's Paul Maholm, also with 26 each. But everybody else in the top five are lefties -- Shields is the only right-hander.
Shields believes the importance of a good pickoff move is undervalued.
"I think every pitcher needs to have a decent pickoff move or just know what's going on over there," he said. "For one, you're going to keep the guy at bay, you're going to be able to set up your double plays, they're not going to steal bags off you and get runners in scoring position. And I treat it as another pitch."
Shields is not one of those pitchers who makes lazy throw after lazy throw to first base, trying to keep a runner close. He only does it when it counts.
"I don't believe in wasting throws," he said.
On Friday night, for example, Shields snapped off a throw that very nearly caught De Aza. Immediately, he threw again -- and got his man.