There might not be a more volatile pitch in baseball than the slider. Good ones become devastating weapons, a wipeout pitch that can turn a starter into a star; bad ones hang in the strike zone before they become souvenirs. It's the pitch most linked to Tommy John surgeries for the stress it puts on a pitcher's elbow, but its allure - more powerful than a curveball, yet more unpredictable than a fastball - is enough to tempt pitchers to master it.
The Chicago Cubs beat the Nationals 5-4 on Tuesday night largely because of that pitch, and the difference between two pitchers' ability to control it. John Lannan couldn't, giving up all five of the Nationals runs on two sliders the Cubs hit out of the park, and Carlos Marmol could, using his devastating breaking ball, delivered from different arm slots, to stop Washington's attempt at a comeback.
It's too simplistic to say the slider decided the game - the Nationals had 23 outs to get something going against Carlos Zambrano and Sean Marshall before facing Marmol - but it certainly contributed to the margin.
Down 5-1 in the ninth inning, the Nationals pulled within a run of the Cubs, giving Ryan Zimmerman a chance to tie the game with a base hit or win it with a homer. But they'd also loaded the bases in the eighth inning, when interim manager Mike Quade called for Marmol to face pinch hitter Ian Desmond with two outs.
Three sliders later, Desmond was making a u-turn back to the dugout, and the inning was over.
"You really can't (sit on it), because he throws 95," Desmond said. "You've just got to look for a ball up in the zone, and cross your fingers, I guess."
Marmol got three of his four outs by strikeout, all on sliders. He tried to put Zimmerman away with two of them in the ninth, but the third baseman barely laid off the first one on a 1-2 pitch before fouling off the second one. Zimmerman squared up a fastball, but he was a hair late to it, sending it to right field where Kosuke Fukudome ran it down to end the game.
"You've just got to pick one," Zimmerman said. "A lot of times, if he would throw three fastballs right down the middle, a lot of people would just go back to the dugout, because you're expecting him to throw a slider at some point. But that's what makes him so dangerous, and that's why he has that many strikeouts."
The Cubs closer has 108 of them in 59 innings, and for his sometimes-adventurous ninth innings, he's got enough mastery of the slider to finish things most of the time for Chicago.
No one would accuse Lannan of having the pitch figured out. By most metrics, it's the worst of his four pitches; its weighted value, according to FanGraphs, was 7.8 runs below average before Tuesday's start, which would be among the worst in baseball if Lannan had enough innings to qualify for the leaderboard.
He hung a pair of them on Tuesday night - one to Alfonso Soriano in the second inning, the other to Tyler Colvin in the fourth. Both of them were hit out, and both of them convincingly.
"The slider to Soriano was right there. He's a great hitter, and I left it right where he can take it out," Lannan said. "And the same thing with Colvin."
The pitches marred an otherwise-solid night for the left-hander, who got eight ground ball outs despite not having good command of the sinker, his best pitch. Forced to go to the slider, he got burned by it.
"John made two bad pitches," Zimmerman said. "John threw well, and you've got to give them credit for hitting the bad pitches he made."
And Marmol worked his slider and fastball as his uppercut and jab, getting the best of the Nationals when it looked like they were about to topple him. On a night when Lannan showed how much trouble the slider can bring you, Marmol displayed its better qualities.
"I know he's going to throw me sliders, and it's a really good one," Zimmerman said. "It's going to start pretty much at you. It's tough to stay in there."