What's wrong with Clay Buchholz?

— -- BOSTON -- Clay Buchholz was unequivocal.

"As far as stuff goes, I feel like I had the best stuff in this start, velocity-wise, that I had all year," the Boston Red Sox pitcher said Wednesday night. "There's absolutely nothing physically bothering me."

So, what is it, then? Manager John Farrell insisted "it looks mechanical in nature," ticking off all the things that Buchholz did wrong Wednesday night: rushing his body ahead of his arm, falling behind too often with pitches up in the zone, finding the middle of the plate with pitches when he did bring them down, lacking the late finish he typically has on his cutter.

And Buchholz again bemoaned the lack of feel for his changeup, a pitch that he has thrown with devastating effect in the past.

"My whole career, my changeup has been my main pitch," he said. "To not have the feel for it every time it's called, that's putting added stress there. I've got to figure out how to find the command and control of the changeup."

But Buchholz is too experienced a pitcher, Juan Nieves too accomplished a pitching coach, and Farrell too in tune with what makes a pitcher tick for them not to have made the necessary corrections by now.

You don't go from being among the most dominant pitchers in baseball at this time a year ago to being a pitching piñata, putting up numbers that rank among the worst in baseball, without there being something more involved than adjusting an arm slot, a grip, a stride or a release point.

The obvious explanation always revolves around an injury. John Lackey endured a hideous beating in 2011 before he finally acknowledged the ligament in his pitching elbow was shredded. And Buchholz's history is already so pock-marked with injuries -- a stress fracture in his back wiping out a huge chunk of his 2011 season, the esophagitis that sent him to the emergency room in 2012, shoulder bursitis shutting him down for three months in 2013 -- that it is reasonable to assume that something is ailing him.

But he swears that there is not. And so does Farrell.

"Physically there are no complaints, no issues," Farrell said.

The power with which Buchholz threw Wednesday would seem to support their contention that Buchholz is not hurt. His velocity averaged 92.8 miles an hour, according to Brooks Baseball data, and maxed out at 95.4. That wasn't the case earlier in the season.

"My arm strength is good," Buchholz said Wednesday. "Whenever I wanted to reach back, I could get to 93, 94."

There are other indicators besides velocity that reveal whether a pitcher is hurt. The extension he gets on his pitches, for example, and whether he is able to maintain his release point. But if there are red flags there with Buchholz, they are not immediately apparent.

So if you accept that he's not hurt, and question whether it can really be all mechanical, then what are you left with?

First, a look at how bad it has gotten:

Buchholz's earned run average of 6.32 is the second-worst among all major league qualifiers to Kevin Correia of the Twins (6.52). He has allowed 71 hits and walked 16 in 47 innings, leaving him with a major league-worst WHIP of 1.85.

• In his past three starts, he has pitched a total of just 15 innings, allowing a staggering 29 hits and seven walks while yielding 13 earned runs.

• After barely throwing his trademark changeup in his past couple of starts, Buchholz threw 10 on Wednesday, only four for strikes -- only one of which induced a swing and miss. Of the 90 pitches he threw Wednesday, the Jays missed only one other, a four-seam fastball.

• By unofficial count, the Blue Jays hit a dozen balls that were either line drives or driven to the warning track or beyond, including two by Edwin Encarnacion that left the premises.

All this from a pitcher whose record through May 22 last season was 9-0 with a 1.73 ERA. But it was in his last start of that month, in Chicago, that Buchholz's physical problems began. He experienced discomfort in his AC joint -- caused, he claimed, by the awkward way he held his sleeping toddler -- was skipped a start, made two more starts in June and then was shut down for three months with what was ultimately described as bursitis.

Obviously, having his head handed to him on a regular basis has taken its toll on Buchholz's confidence, and a pitcher filled with self-doubt when he takes the hill is not a man wired for success. Asked how tough it has been to maintain a positive outlook, Buchholz said:

"Pretty hard. I've been through some ups and downs throughout my career, and I've always found a way to battle back and find where I need to be to be consistent, to go out there and have confidence. ... That's something I'm struggling with."

Farrell often speaks of the importance of a player having his mind free in order to play at optimal level. When your confidence is at low tide, that becomes problematic. From the outside, it's hard not to wonder whether there are other issues that are crowding in on Buchholz, making it more difficult to execute the job at hand. These guys bleed, too.

But if something is out of joint in Denmark, neither Buchholz nor the Red Sox are letting on.

"Obviously, I'm trying," Buchholz said. "I'm not trying to give up home runs to every guy that walks up to the plate."

Wednesday night, Farrell was asked a question that was inconceivable a year ago: If this continues, is Buchholz's spot in the rotation in jeopardy?

"Well, there's no plan at this point to remove him from the rotation," Farrell said grimly. "It's upon us to make the necessary adjustments to eliminate the number of mistakes, the mislocated pitches."