November 14, 2012 at 1:00 am

Kurt Mensching

Rick Porcello's potential, results pose tough questions for Tigers

Tigers right-hander Rick Porcello was 10-12 with a 4.56 ERA last season, his fourth in Detroit. (Elizabeth Conley/Detroit News)

As Tigers executives wind their way through the offseason, they'll have to pay special attention to the case of Rick Porcello.

Porcello has yet to deliver on the promise of a strong rookie campaign in 2009, yet he tantalizes at every turn, making decisions about his future calculated risks.

In 2010, talks of trading Porcello were quickly shot down. At the time, whispers called him untouchable, even when names like Dan Haren or Roy Halladay were floated as possible targets.

Now with Porcello coming off a disappointing 10-12 year with a 4.59 ERA, it's hard to imagine the same untouchable description being applied. Even worse for the Tigers, he is far from unhittable.

What is it about Porcello?

Is it a hope that the kid who wowed in 2009 is still young at age 23 and will eventually return to form?

Is it a belief Porcello has continued to improve each year even as he's slid down the Tigers' rotational ladder?

Which Porcello?

Porcello's case might be a warning about not getting too wed to a player after just one season of competition or a caution that positive indicators in advanced metrics are no guarantee of future success.

Or he might be on the verge of a breakout, ready to finally fulfill on the expectations thrust upon him when the Tigers paid well above MLB recommendation for a No. 27 pick.

Porcello is arbitration eligible and certainly due a pay increase over his $3.1 million salary. Meanwhile with left-hander Drew Smyly knocking on the door and the possibility of re-signing Anibal Sanchez, there might not be a spot for Porcello in the team's future.

The Tigers have a tough case to solve, indeed.

Since a sub-4 ERA his rookie year, Porcello had posted below-average ERAs of 4.92, 4.75 and 4.59 during the next three seasons.

He gave up more hits than ever in 2012, while his strikeout rate improved only modestly.

In the second half of 2012, when the rest of the Tigers rotation was stringing together wonderful start after wonderful start, Porcello pitched into the seventh inning just three times in 14 starts and his ERA was 4.74.

Those numbers do not scream for Porcello to be sent to the minors. They're passable at the bottom of a rotation. But they remain far from what most expected.

Beyond the basics

Advanced metrics paint a better picture of Porcello's career.

Porcello's fielding independent pitching (FIP) stat was a career-best 3.91 in 2012. That's a stat that tries to take defense out of the equation by using the outcomes a pitcher is said to have control over: strikeouts, walks and home runs.

Other similar metrics, such as xFIP and SIERA, also have noted the improvements in Porcello's peripheral stats.

What the stats see is a pitcher who got unlucky when the ball was put into play and a player whose strikeout rate climbed to a career-best 13.7 percent of plate appearances in 2012. (For comparison's sake, a quarter of all plate appearances against Justin Verlander end in a strikeout.)

In other words, while Porcello does not have the profile of an ace, he could be a serviceable middle-of-the-rotation pitcher.

On the other hand, he's pitched "worse" than his FIP in each of the last three years, which is hard to view as a coincidence.

The easiest thing to say is Porcello isn't a good fit for a Tigers club that doesn't feature the most steadfast of defenses, though the addition of outfielder Torii Hunter will help.

Just realize that the infield defense might not be as bad as first thought, if the defensive metric Ultimate Zone Rating (UZR) is to be believed.

Jeff Sullivan noted on Fangraphs.com in September: "Nobody would tell you that (Prince) Fielder or (Miguel) Cabrera ought to be Gold Glove candidates, but as a unit, the Tigers' infield has been just fine, at least if you believe in UZR."

(Whether you should believe in UZR, which rated Jhonny Peralta as the fourth-best shortstop in the MLB, is a question for another day.)

Can Porcello be trusted to finally live up to his rookie hype? Can Sanchez still be re-signed, even after the Hunter signing?

The Tigers have some tough calculations to make to find an answer.

Kurt Mensching is the editor of Bless You Boys, a Tigers blog (blessyouboys.com). He can be reached at bybtigers@gmail.com.