Lifting the Veil of Luck

It's appropriate on the weekend of Black Friday to discuss shopping frenzies. To some extent, every team is in one now as they kick the tires on free agents who might help them win in 2014 and beyond.

One of the most important advances in the world of baseball analytics is the ability of franchise brass to evaluate personnel realistically. When baseball GMs determine which free agents might help their teams in 2014, they will view 37-year-old Bruce Chen with a jaundiced eye.

Teams will know that Chen's 9-4, 3.27 effort for Kansas City in 2013 was a chimera. Nothing in his pitching profile suggested that he had a special season except the ultimate results. In 121 innings he fanned just 78. He relinquished just 107 hits, primarily because opponents batted only .255 on balls in play (BABIP) against him, 25 points lower than his career rate and 40 notches lower than league average. The chasm opens wider when examining only Chen's 15 starts; he made 19 relief appearances to begin the season before the Royals summoned him back into the rotation.

In addition, Chen  stranded 78% of runners who reached base against him, significantly above his lifetime and league average rates. Strand rates are rarely a matter of skill. Finally, an unusually low percentage of fly balls against him left the park, often a sign that a pitcher got lucky with wind, field configuration, and the like.  Taken together, the snapshot of Chen's results provides strong evidence that regression troops are arraying on the border and preparing to attack next season. Caveat emptor.

Likewise, Cubs brass won't be relying on Travis Wood to deliver another stellar (literally: he made the All-Star team) 3.29 ERA season in 2014. Wood also enjoyed a low BABIP (.248), high strand rate (77%) and low fly ball/HR ratio. Advanced statistical models suggest his actual performance looked more like a 4.50 ERA.

Instead, Cubs management might hope for bounce-back from Edwin Jackson. Despite an 8-18, 4.98 campaign in '13, Jackson was actually a strong performer. A .322 BABIP against and a frighteningly low (63%) strand rate conspired to denigrate his work. Fangraphs estimates Jackson was worth two wins above replacement, something an ERA of nearly-five would not suggest.

And don't look now, but 2014's Tiger pitching phenom could be Rick Porcello. The 25-year-old righty managed a 13-8, 4.32 line when everything was going against him; it'll be interesting to see what happens when he basks in the sunshine of serendipity. Like Jackson, Porcello suffered a high BABIP and low strand rate in '13, but big flies are what really did him in. One of every seven balls in the air against him cleared the fences, a miserable rate for which he might not be completely responsible. Fangraphs thinks Porcello was more like a 3.50 ERA hurler who was worth 3.5 wins last year.
Over the last four years, Porcello's strikeout rate has risen while his walk rate has held steady. If he can keep the ball in the park just a little better he has a chance to to some damage in 2014.

Remember, regression is a trend, not a guarantee. Jackson could stink up the joint again and Wood could again leave the bases full of runners. It's just not the way to bet.