Matt Thornton can be trusted as much as any reliever

The White Sox are probably not going to be picking up Matt Thornton’s $6 million option for 2014.

Not that they were ever a sure bet to, but it’s been quite a trip from the moment Thornton inked his two-year extension in Spring Training of 2011, to this current race to get to the end of the contract—if only to renegotiate a lower rate–without Thornton’s ability fading away completely.

In March of 2011, the White Sox had an elite reliever coming off an All-Star appearance, entering into the last year of his contract, and about to become a closer. No reliever getting $5.5 million annually, or what was effectively a three-year commitment, should be taken lightly, but the Sox were praised for getting out ahead of a potential windfall for the best bullpen guy. They paid Thornton to be an elite reliever before they might have to suffer whatever extra bonuses the ethereal label of proven closer might afford him. And with his skill set, and even success in closer cameos, they had every reason to believe he would earn that label.

Of course, as Thornton admitted about his experience as a closer, “things have not gone right.” Beyond the zaniness of the defense that more or less became a scatter band behind him during save situations, Thornton’s command wavered badly in the first half of 2011, and even his recovery suggested that 2010 was probably a peak season, not a new level of mastery. It’s odd to speak ill of a season where Thornton’s FIP and xFIP were both below 3.00, but it was the first blip on his resume in three years, and offered uncertainty–beyond general concern about his age–to his performance over a contract that was expected to be a bargain.

But 2012 is what really jiggled the circuits in regards to how Thornton can be conceived of as a pitcher. In terms of velocity, strikeouts, swinging-strike rate, and runs allowed, it was all Thornton’s worst work since 2007, but it featured a significant alteration is his approach. Another mile ebbed away from Thornton’s fastball, but he also took a large step away from throwing the heat nine out of every 10 times as he did before, and tried to work in a slurvy slider that varied between effectiveness and just being a strike-grabbing offering. The all-conquering fastball approach was gone, and with it–and no change-up–Thornton’s platoon situation downgraded from Chris Sale status (good against righties, pointless slaughter against lefties), to where handedness needed to be considered before bringing him in the game.

It’s hard to think of where to map Thornton’s performance from here, because the transitional nature of his approach is mixed with evidence of his decline. He could continue to lose his fastball, he could continue to develop secondary offerings that he didn’t give much thought to when he was blowing everyone away. The forces of his depreciation are probably stronger than his adjustments–he’s 36, for goodness sake–but by what degree?

The point of bringing up the contract is largely to emphasize the speed of the shift. Within a two-year span, an elite, feared reliever with solid peripherals and a sustained track record of success went through a thorough transformation–especially in the way he’s regarded by the fans.

Meanwhile, Jesse Crain–an intense fly ball pitcher in U.S. Cellular Field who puts runners on base by the truckload, was signed to a three-year deal after a peripheral-defying, low-ERA season in pitcher-friendly Minnesota, has gone right ahead and had two-straight intense fly-ball, walk-heavy, peripheral-defying, low-ERA years in Chicago. Jesse Crain, with all of his periods of not being able to throw a strike, half hour long innings and #Crainwreck hashtags, has a 2.54 ERA as a member of the White Sox.

Relievers are volatile, very volatile. It’s a concept that seems wildly accepted, if only from looking at the contract lengths that shudder to go three years, let alone beyond. But despite our best attempts to intone this principle, real life examples blow our already altered expectations away.

Follow James Fegan on Twitter @JRFegan