Changeup key to Clay Buchholz's surge

Clay Buchholz is 3-1 with a 2.03 ERA in seven starts since the All-Star break. AP Photo/Tony Dejak

One of the hottest pitchers the last couple of months has been Boston Red Sox right-hander Clay Buchholz, who has engineered a startling turnaround from earlier in the season, where he appeared to be one more bad start away from a demotion.

Ever since debuting in the majors and twirling a no-hitter against the Orioles in his second career start in 2007, he's been considered one of the better young pitchers in the game. Unfortunately for Buchholz, that instant success didn't help him avoid the injuries and inconsistency that has plagued his career since. There's no denying his talent when he's right, however, and that's the very reason Boston inked him to a four-year contract extension in 2011.

The first year of that extension didn't start off well, as he began 2012 with a brutal 7.19 ERA in his first 10 starts. Despite being interrupted by inflammation of the esophagus that landed him on the disabled list for close to a month, Buchholz hasn't been the same pitcher since the beginning of June, posting a pristine 2.16 ERA in 11 starts. But what changed? How did Buchholz suddenly go from one of the worst pitchers in the game to one of the best?

The answer is fairly complicated, but there are two partial explanations that jump out after looking at the data. The first is that Buchholz rediscovered the effectiveness of his changeup by virtue of throwing a split-fingered fastball, and the other explanation is pure dumb luck.

Buchholz entered the season with a changeup as his bread and butter pitch, as it had been for much of his career. However, he struggled to establish the change in the early going. Hitters were thoroughly unimpressed, putting the ball in play much more frequently and robbing the right-hander of his out pitch. He also struggled mightily to find the strike zone, racking up a 4.47 walk rate per nine innings through the first two months after posting a career-low rate of 3.38 in 2011.

"It's just the little things that maybe you can't feel or can't see, but [the changeup is] really not the same as it used to be," Buchholz told the Providence Journal in early June about his struggles with throwing his changeup.

But Buchholz finally solved his problems with the pitch, and it was thanks to Josh Beckett. (Imagine that, Beckett actually contributed positively to the 2012 Red Sox for a change.)

Buchholz approached Beckett for advice on how to throw the split-finger fastball. Using Beckett's grip, Buchholz started to incorporate his splitter more. It gave him a fifth pitch and forced hitters to contend with a second off-speed offering. Buchholz threw his change for more strikes -- finding the zone at a clip of 10 percent higher than earlier in the season -- and hitters struggled to put the ball into play.

The splitter retains more velocity than the change and runs to the opposite side of the plate, while the changeup dives down and into left-handed batters. Before rediscovering his change, the pitch was staying essentially flat without any horizontal movement. Pitches that stay straight like that generally get hit a long way.

Part of what might be helping is a change in his release point. Earlier in the season, Buchholz was throwing from a three-quarters motion. It was fairly similar to his release point last season, if not a bit lower. But since turning his season around, Buchholz has thrown from a completely different angle, moving his arm closer to his head to an overhand release point. What that has done is hide the ball more effectively from hitters, giving them less reaction time to figure out what pitch is coming. In addition, it allows Buchholz to throw on more of a downward plane straight toward the plate, sacrificing movement for accuracy. And indeed, Buchholz's 1.84 walks per nine innings since June 1 is a large reason for his success. Limit the amount of runners you put on base, and you limit the amount of runs that can score.

But Buchholz has also benefited dramatically from luck. There are three metrics I like to look at when I figure out how lucky a pitcher has been. Those are batting average on balls in play (BABIP), left-on-base percentage and home runs per fly ball.

Roughly 30 percent of all balls -- or .300 in batting-average parlance -- land for hits regardless of how good the pitcher is. There are always exceptions with many different causes, including defense and luck. By and large, any figure that isn't around .300 is due for correction, but if a pitcher has established a baseline for his own work, as Buchholz has done with a career .281 BABIP, that baseline should also be taken into consideration. As you can see from the table, Buchholz’s BABIP luck has dramatically swung from one extreme to the other.

It's also generally accepted that a pitcher's left-on-base percentage should hover in the mid-70s and any differences are a product of luck. In the last three months, he's really benefited from stranding runners. Of course, part of his improvement also comes from better pitches and better location. It's the same story with home runs per fly ball. HR/FB varies on a yearly basis, but the average is generally accepted to be around 9.5-10 percent, according to FanGraphs. The table bears out once more that Buchholz has swung from being unlucky to lucky.

All this is not to shroud Buchholz's dramatic improvement in a cloak of luck. It would be far too simple to say Buchholz's resurgence is due to luck, just like it would be foolhardy to point to his disastrous start to the year as all luck. The truth is that Buchholz was rather unlucky early on and has benefited from luck since, but the underlying changes are what are far more important and are what will matter to Buchholz's future. He's rediscovered his changeup, and in the process, discovered another weapon in a split-fingered fastball he can use to get batters out. In a season to forget, the Red Sox may all look back on 2012 as the year Clay Buchholz became the best right-handed pitcher on the Red Sox staff for years to come.