Spitballing: Position changes June 3, 2011
Posted by tomflesher in Baseball.Tags: Alex Rodriguez, Angel Pagan, Buster Posey, Carlos Beltran, Derek Jeter, Jorge Posada, Kenley Jansen, Luis Castillo, Spitballing, Stuff Keith Hernandez Says
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First thing’s first: this entry was prompted by Buster Posey and his horrific ankle injury, but it’s not just about him. The first time I started thinking about it seriously was last year, when the Mets’ Carlos Beltran was about to come off the DL and Angel Pagan‘s placement was in doubt. Either Gary, Keith, or Ron tripped my “Stuff Keith Hernandez Says” meter by saying that fans had suggested moving Pagan to second base to fill in for the ailing Luis Castillo, and commented that “You can’t just move a guy to second base.” Very true.
Similarly, it’s very hard to “just move a guy” to catcher, which is why a guy like Buster Posey is so valuable. In the National League, the median OPS+ for players with at least 100 plate appearances and who played more than half their games at catcher was 91. Posey’s OPS+ was 129 – that’s over 40% better. If instead you look at first basemen with at least 100 plate appearances, the median OPS+ is 107. All of a sudden, Posey’s offensive value-added drops to about 20% above average, and that’s before accounting for regression to the mean. Moving him to third base instead mitigates the damage and takes full advantage of his arm, but he’s suddenly a much less special player when he’s on the hot corner instead of behind the plate.
It’s also maddening to hear about efforts to move Derek Jeter to center field. Even though he’s on the downswing, he’s hit well above average every year from 1996 through 2009. Even last year, his 91 OPS+ was acceptable, especially considering his popularity. Granted, he costs his team runs on defense (he’s rarely had a positive defensive Wins Above Replacement), but his offensive contribution more than makes up for it. He’s 6’3″, making him more than big enough to move to first base, and first base doesn’t require him to have the range that center field would. After Jorge Posada hangs it up, splitting the duties at first base and DH between Jeter and Alex Rodriguez will start to make more sense, and using homegrown prospects to take over at shortstop and third base ensures continuing fan loyalty.
Finally, I’d be remiss if I didn’t mention future Dodgers closer Kenley Jansen. Although his 2.000 OPS last year grossly overstated his batting ability (only two plate appearances, compared with a lifetime .229 batting average in the minors), Jansen is a success story in his move from catcher to fireballing reliever. That was an excellent move by the Dodgers system – they took Jansen’s innate ability (his cannon-like arm) and moved him to a position where his contribution would be optimized. Whether or not Jansen turns out to be a future dominant closer, he’s probably gotten more playing time as a reliever than he ever would have as a catcher, and he’s generated more value for the Dodgers.
Basically, player moves are difficult. It’s important to try to optimize a player’s contribution, and that needs to take into account his defensive talents instead of merely trying to find a place for him to play. I can only hope Buster Posey’s recuperation goes smoothly and there’s a value-maximizing slot for him with the Giants.
Back when it was hard to hit 55… July 8, 2010
Posted by tomflesher in Baseball, Economics.Tags: Baseball, baseball-reference.com, home runs, R, regression, sabermetrics, Stuff Keith Hernandez Says, talent pool dilution, Willie Mays, Year of the Pitcher
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Last night was one of those classic Keith Hernandez moments where he started talking and then stopped abruptly, which I always like to assume is because the guys in the truck are telling him to shut the hell up. He was talking about Willie Mays for some reason, and said that Mays hit 55 home runs “back when it was hard to hit 55.” Keith coyly said that, while it was easy for a while, it was “getting hard again,” at which point he abruptly stopped talking.
Keith’s unusual candor about drug use and Mays’ career best of 52 home runs aside, this pinged my “Stuff Keith Hernandez Says” meter. After accounting for any time trend and other factors that might explain home run hitting, is there an upward trend? If so, is there a pattern to the remaining home runs?
The first step is to examine the data to see if there appears to be any trend. Just looking at it, there appears to be a messy U shape with a minimum around t=20, which indicates a quadratic trend. That means I want to include a term for time and a term for time squared.
Using the per-game averages for home runs from 1955 to 2009, I detrended the data using t=1 in 1955. I also had to correct for the effect of the designated hitter. That gives us an equation of the form
The results:
| Estimate | Std. Error | t-value | p-value | Signif | |
| B0 | 0.957 | 0.0328 | 29.189 | 0.0001 | 0.9999 |
| t | -0.0188 | 0.0028 | -6.738 | 0.0001 | 0.9999 |
| tsq | 0.0004 | 0.00005 | 8.599 | 0.0001 | 0.9999 |
| DH | 0.0911 | 0.0246 | 3.706 | 0.0003 | 0.9997 |
We can see that there’s an upward quadratic trend in predicted home runs that together with the DH rule account for about 56% of the variation in the number of home runs per game in a season (
Then, I needed to look at the difference between the predicted number of home runs per game and the actual number of home runs per game, which is accessible by subtracting
This represents the “abnormal” number of home runs per year. The question then becomes, “Is there a patt
ern to the number of abnormal home runs?” There are two ways to answer this. The first way is to look at the abnormal home runs. Up until about t=40 (the mid-1990s), the abnormal home runs are pretty much scattershot above and below 0. However, at t=40, the residual jumps up for both leagues and then begins a downward trend. It’s not clear what the cause of this is, but the knee-jerk reaction is that there might be a drug use effect. On the other hand, there are a couple of other explanations.
The most obvious is a boring old expansion effect. In 1993, the National League added two teams (the Marlins and the Rockies), and in 1998 each league added a team (the AL’s Rays and the NL’s Diamondbacks). Talent pool dilution has shown up in our discussion of hit batsmen, and I believe that it can be a real effect. It would be mitigated over time, however, by the establishment and development of farm systems, in particular strong systems like the one that’s producing good, cheap talent for the Rays.
Trends in DH use June 11, 2010
Posted by tomflesher in Baseball, Economics.Tags: Baseball, baseball-reference.com, designated hitter, economics, Interleague play, Mets, regression, sports economics, Stuff Keith Hernandez Says
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Last night, Keith Hernandez was talking about how the Mets are scheduled to play in American League parks starting, well, today. He pointed out that the Mets will be in a bit of a pickle because they aren’t built, as AL teams are, to carry one big hitter to be the full-time DH. Instead, an NL team will be forced to spread the wealth among lighter hitters who are carried for their defensive acumen as well as their offensive prowess. Keith then corrected himself and said that AL managers are using the DH differently – to rest individual players instead of having an everyday DH.
That pinged my “Stuff Keith Hernandez says” meter, and so I decided to crunch some numbers and see if that’s true. I interpreted Keith’s statement as implying that the number of designated hitters should be increasing, since managers are moving away from an everyday DH and toward spreading the DH assignments around a bit more. The crunching also needs to account for interleague play, which should obviously increase the number of DHes. So, after controlling for interleague play, does DH use show an increasing trend with time?
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