You may have read my recent article on Ichiro, where I use my new stat, Ultimate Value Index, to make sense of one of the most unique players the game has ever seen.
One thing that makes baseball great is the wide variance of career paths. Some players have their career years at age 23; others peak at 36. You just can't make assumptions about players getting better or worse.
One case of an early peak is Giants lefthander Barry Zito, whose three best years came right at the beginning of his career, culminating in his AL Cy Young Award in 2002 at age 24.
Since that year, Zito has mysteriously morphed into a average pitcher. He signed a 7-year, $126 million deal with the Giants prior to the 2007 season, and switching leagues only seemed to accelerate his decline.
Why has Zito gone downhill? Or has he gone downhill at all? Was he just lucky for three years?
If you're familiar with my writing, you are probably familiar with my new statistic, Ultimate Value Index (UVI). In this article, I discussed some basic facts about First-Order Pitching UVI and Adjusted Lines.
I figure that Adjusted Lines could provide some insight on if Zito has truly declined, or if he was just lucky from 2000-02, or just unlucky from 2003-present.
As with Ichiro, I am going into this article with no preconceived notions; I'm letting the numbers do the talking, and I'll make sense of them afterwards. I've always liked Zito and never had any issues with Ichiro, whether or not Ichiro is "great" or simply "good."
Barry Zito's Adjusted Lines (UVIs are all UVI1)
2000: 86.3 IP, 83 H, 1.48 WHIP, 4.41 ERA, .314 BABIP, .243 AVG, .334 OBP, .357 SLG, .691 OPS, .434 UVI
2001: 210.7 IP, 195 H, 1.31 WHIP, 4.18 ERA, .314 BABIP, .236 AVG, .313 OBP, .360 SLG, .673 OPS, .425 UVI
2002: 218.3 IP, 215 H, 1.34 WHIP, 4.40 ERA, .313 BABIP, .247 AVG, .316 OBP, .391 SLG, .707 OPS, .446 UVI
2003: 217 IP, 230 H, 1.47 WHIP, 4.56 ERA, .313 BABIP, .261 AVG, .332 OBP, .393 SLG, .725 OPS, .451 UVI
2004: 211.7 IP, 220 H, 1.42 WHIP, 4.76 ERA, .318 BABIP, .257 AVG, .328 OBP, .419 SLG, .747 OPS, .474 UVI
2005: 216.7 IP, 220 H, 1.43 WHIP, 4.71 ERA, .315 BABIP, .253 AVG, .331 OBP, .405 SLG, .736 OPS, .467 UVI
2006: 214.7 IP, 230 H, 1.53 WHIP, 5.03 ERA, .318 BABIP, .263 AVG, .347 OBP, .421 SLG, .768 OPS, .487 UVI
2007: 190 IP, 202 H, 1.50 WHIP, 4.87 ERA, .315 BABIP, .262 AVG, .336 OBP, .420 SLG, .756 OPS, .478 UVI
Career: 1589.3 IP, 1617 H, 1.43 WHIP, 4.63 ERA, .314 BABIP, .253 AVG, .329 OBP, .399 SLG, .728 OPS, .460 UVI
Before I go on, I'd like to remind you two things about the ERA: First, it's very crude, unlike everything else here, and second, it's actually RA, because it doesn't count defense.
So yes, Zito's ERAs should have been slightly better than that, but everything else is exactly where it should be. Also, remember that walks, strikeouts, homers allowed, HBPs, and groundball percentage remain the same.
So what does this tell us? First of all, you'll notice there is no big drop between 2002 and 2003. Also, 2002 was not Zito's best season. In fact 2001 turned out to be the best year of Zito's career to date, which is even more extraordinary.
The dropoff from 2002 to 2003, was in fact far less severe than the dropoff from 2001 to 2002, or from 2003 to 2004.
We can rank Zito's years like this:
It's interesting that Zito's worst year was his contract year. Baseball Prospectus has found that players historically perform better in contract years, so Zito bucked that trend as well.
One thing is true: Even after adjusting for luck, the first four years of Zito's career were the best. However, as the UVIs show, Zito was never really a tremendous pitcher. Even at his best in 2001, Zito pitched like a No. 2 starter.
The difference between 2001 and 2006, UVI-wise, is .062. That's significant, but it's just the difference between a No. 2 and a No. 4. Zito, even at his worst, was still a good player to have in the rotation.
Why exactly was he worse from 2004-07 than from 2000-03? Several reasons. 2004 and 2007 featured bad home run rates, and 2006 saw Zito's walk rate balloon.
Notice that 2005, the season where Zito kept both the walks and homers in check, he had a better year than any year since 2003. There, however, 13 HBPs didn't help his OBPA.
From 2000-03, Zito's Expected SLG was below .400 each year. Since, it's been above .400 each year. You can see that in 2003, his AVG and OBP against had already started to decline, but his low home run rate kept his overall value close to 2002 levels.
When the homers ballooned in 2004 and nothing else changed, his slugging percentage also increased, causing his performance to hit a new low. Since then, Zito hasn't really improved on anything enough to turn his career really around.
The popular notion that Zito is "getting worse" may have something to it, given that his '06 and '07 are worse than his '04 and '05, but the notion that he crumbled upon going to SF is incorrect, as he fixed his walk rate upon switching leagues, and dramatically cut his HBPs.
Facing weaker lineups in the NL, this should be expected, but Zito was actually better in 2007 than he was in 2006.
The fact remains, however, that Barry Zito is indeed just a No. 4 starter who's getting paid to be an ace. His career path, although not as exaggerated as one would think, does not lend hope that he will ever meet the expectations reflected by his contract.