Porcello Poised for a Breakout?

Porcello has been ace-like during spring training. Will he carry that performance over into the regular season?Should the Tigers trade Rick Porcello?  They'd have to be nuts to do that, according to Ken Rosenthal of Fox Sports. Porcello has whiffed 18 batters, walked none and posted a 2.50 ERA in 18 major league innings this spring. Rosenthal thinks he could pitch like an ace in 2013:

Tigers right-hander Rick Porcello, the subject of trade speculation, started the minor-league game because it was his day to pitch and the parent club was off.

Yet it quickly became evident — as it has been evident all spring — that if the Tigers move Porcello, they’re nuts.

...

What matters is Porcello’s aggressive, self-assured demeanor. What matters is the carry on his four-seam fastball, the snap in his curveball, the indications — one after another — that he is on the verge of a career breakthrough.

Is Rosenthal right to get his bowtie in a twist over Porcello's potential, or will 2013 be another so-so season for the 24-year-old righty? Here are three reasons why Porcello will break out -- and three reasons why he won't.

Why Porcello Will Break Out

• Porcello's strikeout rate has climbed three years running, from 12% of batters faced back in 2010 to 13.7% this past year. Much of the credit for that increase goes to his fastball. Porcello threw his heater harder last year, and hitters started whiffing at the pitch more often. 

  Porcello's Fastball

  Porcello notched 72 Ks with his fastball in 2012, up from 55 in 2011 and 53 in 2010.

• As Rosenthal mentioned, Porcello is scrapping his slider in favor of his curveball. That's probably a wise move, considering that every hitter who saw a slider from Porcello last year morphed into Miguel Cabrera. Batters slugged .633 against Porcello's slider in 2012, by far the highest mark among starters. Porcello's curve fared much better, albeit in a limited sample size (.313 opponent slugging percentage).

  Curveballs also tend to be effective against batters on both sides of the plate, unlike sliders (see chart below). That could help Porcello tame lefty batters, who crushed him for a .503 slugging percentage last year (righties slugged 100 points lower).

   Right-handed starting pitchers throwing breaking pitches, 2012

• Porcello's changeup has become more of a chase pitch over the years, a development that could also help him keep lefties at bay. Batters lunged at 29% of changeups that Porcello threw out of the strike zone in 2010, 32% in 2011 and 39% in 2012 (the MLB average is 35-36%). For comparison's sake, Justin Verlander got hitters to chase his changeup 38% of the time last year.

Why He Won't

• As a low-strikeout, worm-burning pitcher, Porcello couldn't ask for a worse home than Detroit. It's great to have Prince Fielder and Miguel Cabrera providing run support. But let's be honest -- Prince and Miggy aren't getting any younger, swifter or slimmer. They'll have statues outside Comerica Park one day, but they're already statues in the field. Tigers pitchers had a collective .260 Batting Average on Balls in Play on ground balls last year, fourth-worst among MLB clubs and 15 points above the big league average. Porcello had a .250 BABIP on grounders.

  The Tigers ranked near the bottom in converting ground balls into outs in 2010 and 2011, too, which is a major reason why Porcello's ERA has been higher than his Fielding Independent ERA (FIP) in each of the past three seasons. Porcello's three-year ERA is 4.75, and his FIP is 4.09. AL starters have an ERA of 4.28 over the same time frame. He's a slightly above-average pitcher stuck behind lousy defenders, which makes him look below-average. Will that change in 2013?

• Porcello is missing more lumber, but so is every other pitcher. Overall, AL starting pitchers struck out 17.1% of batters faced in 2010. Last year, they punched out 18.2%. Porcello's strikeout rate was about 30% below the league average in 2010 (see table below). Last year? About 25% below average. When you consider the increase in Ks across the game, Porcello is more treading water than making marked progress.

  Porcello's K rate compared to the AL average for starters

• Rosenthal mentions that Porcello is one of just five pitchers to tally a double-digit win total in at least four consecutive seasons before turning 24, putting him in the same company as Hall of Famers Bert Blyleven, Chief Bender and Dennis Eckersley. Is Porcello really in the same class as those pitchers, though? Consider Porcello's career stats through age 23, compared to that trio of Hall of Famers. I used Baseball-Reference's ERA+ stat to make an apples-to-apples comparison. ERA+ adjusts a pitcher's ERA for league and park factors, putting it in on a scale where 100 is average, below 100 means the pitcher is worse than average, and above 100 means he's better.

  Porcello, Blyleven, Chief and Eck through age 23

  Source: Baseball-Reference  

  Bender was about average for his era, while Blyleven and Eckersley were top-shelf starters during their early twenties. Porcello gets dinged here a bit for the aforementioned lousy defense behind him, but he's still not in the same class. Bender, Blyleven and Eckersley also routinely ranked in the top 10 in strikeouts during the eras in which they played. Porcello hasn't shown the ability to dominate hitters like that.