Changing Speeds: Buzzkill-o-Metrics

Tuesday night in front of a full house at Wrigley Field, Carlos Zambrano successfully stared down the San Francisco Giants in a game the visitors desperately needed to win to maintain their wafer-thin divisional lead. While the Giants eventually scored a critical 1-0 victory, the fault didn’t lie with Zambrano, who managed to shut them out on three hits over six innings, and whose eight strikeouts gave him 1,431 for his career—one behind Charlie Root for second place on the all-time Cubs K-list.

Big Z’s big game performance was just the latest chapter in one of journalism’s most beloved narratives: the prodigal son. Zambrano’s season has been a roller coaster ride, starting with an Opening Day shellacking at the hands of Jason Heyward and the Braves, followed by a nearly unprecedented move to middle relief, then back to the rotation before a dugout confrontation with Derrek Lee caused the Cubs to place him on the restricted list. While undergoing anger management counseling to take the edge off his sometimes-petulant personality, Zambrano has returned to the rotation and thrived, winning six of his nine starts while posting a microscopic 1.74 ERA. It’s a story everyone loves, and if the basic narrative structure holds true it should end with the Cubs embracing their always-entertaining but oft-distracting ace, penciling him into the front of their 2011 rotation, feasting on fatted calf, and being rewarded for their faith with the type of dominance Zambrano has displayed in the season’s final days.

But how dominant has he been, really? This kinder, gentler Zambrano 2.0 has been unquestionably effective at preventing runs in the five weeks since his return from the analyst’s couch. Here are his numbers as a starter—ignoring his ill-conceived April banishment to the pen—before and after his dugout eruption:

Just watching Zambrano work on Tuesday, you could see evidence of a different approach. His mound demeanor, which had once been punctuated by fits of pique after fielding plays or umpire calls that bothered him, appeared somewhat calmer. He worked his way out of two bases-loaded jams, and gave only a minimal (and possibly supportive) reaction when rookie shortstop Starlin Castro took a bad first step on what became a ground ball single to his right off the bat of Pablo Sandoval—a response similar to his mentoring and forgiveness of Castro several starts ago for a missed tag. Zambrano himself seems a changed man in his interviews as well, talking at length about the illness affecting his young nephew in Venezuela and his excitement at his mother’s impending visit to the U.S. to see him pitch in person for the first time in his major league career. All of which is terrific for Zambrano the man, but has it really been the driving force behind a resurgence of Zambrano the pitcher, such that the Cubs should bet on him continuing his recent performance?

I don’t want to harsh anyone’s mellow, but here’s that table again, with a few more columns added:

As you can see, since his return Big Z has been walking more batters and striking out fewer than he had been during his early-season struggles. His ground-ball rate has gone up slightly, which generally leads to a lower BABIP, but not enough to explain a drop of 130 points. Zambrano’s home-run rate per fly ball had been ghastly before his mid-season blow up, but is now unsustainably low. If you looked at these numbers with no knowledge of Zambrano’s back story, you’d make the assumption that his results were far worse than should be expected early in the season, and far better than should be expected since his triumphant return. His win total and ERA may have told a Jekyll and Hyde story this year, but the rest of his numbers have a different tale to tell. In fact, when you look at his 2010 season as a whole, he’s pretty much the same pitcher he was last year:

I’d be hard-pressed to find a pitcher whose 2009 numbers were as close a match to 2010 as Zambrano’s have been. As much as we might like to think that Zambrano has suddenly turned a corner, that his numbers prior to forcibly seeking help were sabotaged by his demeanor, and his numbers afterward have been bolstered by a newfound ability to focus and perform under pressure, the greatest likelihood is that his current success is a sample size fluke. He’s probably still the same pitcher he’s been in the recent past, and he’ll be that same pitcher in the near future.

Look, there are certainly those who can look at the tables above and decide that I’m a flint-hearted killjoy, unable to enjoy the fact that Zambrano is getting good results and leaving it at that. Nothing could be farther from the truth. Those wins, those outs, those big pitches he’s made lately to get out of bases-loaded jams, those warm fuzzies—they all happened, and as a fan I’ve certainly enjoyed them. But championships aren’t built on a framework of warm fuzzies. If they were, you’d think the Cubs would have won at least one of them in the last century. It’s the future I’m concerned with here, and what the Cubs certainly need to be concerned with. Zambrano’s wins, ERA, and WHIP aren’t particularly predictive of how he’ll pitch next year. Walk rate, strikeout rate, ground-ball rate, home-run rate—years of analysis by people smarter than me have shown that those things are far more predictive, and what they have to say about Zambrano’s recent performance isn’t very reassuring. It’s certainly possible that the warmth and light that has seemingly entered Big Z’s life makes him perform better in pressure situations, that he’s become the Uncarved Block and his newfound Taoist calm allows him to keep putting zeroes on the scoreboard despite some clearly shaky peripherals. I’d like that to be true. It’s possible, sure, but it’s not particularly likely. Sometimes the narrative we want doesn’t match the truth we face, and when they soberly plan for 2011 the Cubs will need to know the difference.

 Next Time on Buzzkill-o-Metrics: Jeff Samardzija’s K/BB ratio, his recent “successful” big-league starts, and the existence of Santa Claus.