My latest Stros review noted Stros skipper Phil Garner‘s limitations as a big-league manager. A reader asked me to elaborate.
First, let me be clear that I like Garner. He is a genuinely nice man and he represents the Stros well. He’s not the worst recent Stros manager by any stretch of the imagination (remember Jimy Williams?). He is just not as good a manager as Larry Dierker.
Apart from allowing the odious Mike Gallo (5.74 ERA/-3 RSAA) and Trevor Miller (4.63 ERA/0 RSAA) to be on the same pitching staff together, Garner gave us a good example of his limitations in the following recent Chronicle blurb regarding two of the Stros’ underachieving outfielders, Preston Wilson and Jason Lane:

For those fans wondering why Phil Garner is giving Preston Wilson steady playing time and sitting Jason Lane, Garner mentions Wilson’s track record as a major-league run producer.
In contrast, Lane has been a major-league starter for only one season.
“I’ll give him every chance I can to get on a roll,” Garner said of Wilson, who responded Thursday by going 4-for-5 with a double, two runs, an RBI and two stolen bases. “He’s been a productive player. I’ll give him every chance I can to keep being a productive player.”

So, Garner prefers Wilson over Lane because of “Wilson’s track record as a major-league run producer.” There is only one problem with that analysis.
It’s wrong.
Wilson, who is almost 32 and became a regular National League player at the age of 24, has been a below-average National League hitter and run producer for his entire MLB career — he has scored 17 fewer runs than an average National League player would have during the time Wilson has been an MLB player (RCAA, explained here). Wilson has been a below-average run producer while possessing a below-average .331 on-base average, an above-average .473 slugging percentage and an above-average .805 OPS (i.e., on-base average + slugging percentage).
Meanwhile, Lane, who is 29 and has been a regular National League player for one season, has been an above-average National League run producer for his two full major league seasons. He has a 14 RCAA while generating a below-average .328 on-base average and an above-average .488 slugging percentage and .816 OPS.
Moreover, even though Lane and Wilson are not having good seasons to date this year, Lane is clearly better than Wilson. Lane’s RCAA this season is -2 and he has an above-averge .341 OBA, although his slugging percentage and OPS are below-average at .431 and .771. In 191 plate appearances, Lane has made 129 outs and generated 31 hits, including 9 yaks and 4 doubles, while taking 32 walks, second on the club to 3B Morgan Ensberg. Lane has struck out 32 times and grounded into one double play.
In comparison, Wilson’s RCAA this season is -7 and his other numbers are equally atrocious — a .305 OBA, a .392 SLG, and a pathetic .697 OPS. In just 12 more plate appearances than Lane, Wilson has already made 19 more outs (second on the club only to the equally ineffective-hitting Taveras) while generating 51 hits, only 11 of which have been for extra bases (including five yaks). Wilson has drawn only 9 walks, which is the worst on the team among regular players, and his 56 strikeouts leads the team by far. One good thing about Wilson’s high strikeout rate is that at least it keeps him from hitting into double plays, which he has already done five times this season.
In addition to all that, Lane is a clearly superior defensive player to Wilson.
Consequently, Garner favors a less productive singles hitter (Wilson) over the slumping but more productive power hitter (Lane) because of the myth that Wilson is a “proven Major League run producer.’ Inasmuch as I do not believe Garner is a disingenuous man, my sense is that he truly believes that Wilson has been the more productive player. That he doesn’t understand that Lane has clearly been the more productive player reflects one of Garner’s limitations as a manager — relying on myths rather than analyzing performance accurately.
Jimy Williams’ disastrous decision to platoon the extraordinarily productive Ensberg with the notoriously unproductive Geoff Blum during the 2003 season may well have cost the Stros a playoff berth that season (the Stros finished one game behind the Cubs that season in the National League Central race). The difference in productivity between Lane and Wilson that Garner faces is not as great as the difference between Ensberg and Blum that Williams faced in 2003, but — particularly in a close race for a playoff berth — these types of managerial mistakes can make a difference.