Buchholz's slider has become a plus pitch

Ask anyone associated with the Red Sox, and they'll tell you the key for Clay Buchholz has been the command of his fastball.

"This kid was told what he needed to do, what he needed to work on in (the) Arizona (Fall League) and what he needed to do in offseason: He need to command the fastball," said Rich Sauveur, the pitching coach at Triple-A Pawtucket. "That's what he did. He came down to Fort Myers and established his fastball early on and then would go to his secondary pitches."

"He’s using his fastball more effectively, commanding it better, and he has more confidence in the pitch," said Ben Cherington, Red Sox senior vice president and assistant general manager. "His secondary stuff has always been so good that he’s been able to get away with pitching without using the fastball as much, and he hasn’t been as comfortable with it. Against major-league hitters, the margin for error is smaller, and he struggled when he was not using his fastball effectively to set up his other pitches."

But along with that fastball has come improved velocity and command of his slider, and that means Buchholz is throwing four pitches that are or are on the verge of becoming real weapons against major-league hitters.

The last of those plus pitches to come along? His slider.

Against Toronto on Saturday, Buchholz threw seven sliders. Four were down and out of the strike zone but not chased. Two were swung at and missed.

For the sake of comparision, Buchholz threw 19 curveballs and got just one swing and miss, and he threw 52 fastballs and got just one swing and miss.

(The point of throwing his fastball, to fair, is not to get swings and misses. The point is to get weak contact and to set up his secondary pitches so hitters can't sit on anything offspeed.)

His best swing-and-miss pitch was his changeup (a remarkable 12 swinging strikes out of 25 pitches), but his second-best swing-and-miss pitch was his slider.

Buchholz has never thrown his slider with this type of effectiveness. This isn't a contrast between the major leagues and the minor leagues, either: This is a young pitcher mastering a fourth pitch that might just make him a star.

Here's Buchholz against the Royals in early August last season:

There's virtually no difference between his curveball and his slider. The purple dots and the orange dots run together -- it's as slurvy as it gets.

"I would call (the slider) more of a hard curveball last year that came from a different arm angle," Sauveur said. "This year, he went with all of his pitches to the same arm slot, and it became a true slider that he's throwing now. ... His curveball is a hard curveball, a 12-to-6, and to make it a slider, all he was doing was dropping his arm."

Here's Buchholz against the Blue Jays on Saturday:

He's certainly throwing his fastball with better command as evidenced by the tight grouping of the green dots in the top left corner. But his secondary pitches no longer all blend together: His slider comes in at 85 miles an hour with a certain type of movement, and his curveball comes in at 78 miles an hour with a different type of movement.

It makes it very difficult for a hitter to go up guessing -- and it makes it even more difficult for a hitter to find patterns the way hitters seemed to find patterns against Josh Beckett earlier this month.

The last time Buchholz pitched at Tropicana Field, he turned in easily the best outing of his otherwise miserable 2008 season. He absorbed the loss but through no fault of his own: He shut the Rays out through the first seven innings but allowed a two-run home run to Akinori Iwamura with two outs in the bottom of the eighth.

He walked two in the first inning but got out of the jam by striking out Evan Longoria, and he retired 19 of the next 20 hitters he faced.

Another outing like that -- or like his sensational effort against the Blue Jays on Saturday -- would all but solidify his standing as the No. 3 starter in the Red Sox rotation for the indefinite future.