In theory, switch hitting makes a player immune to the handedness of pitchers so a manager will get no distinct advantage out of bringing in a specialty reliever from the bullpen in an attempt to increase the percentages of the reliever recording an out. If a left-handed reliever comes into the game, then the hitter can bat from the right-handed batter's box or vice versa.
The same holds true for switch hitters versus opposing starting pitchers. A left-handed switch hitter need not have been taken out of the lineup when facing vintage Randy Johnson. That being said, switch hitting is only effective when a hitter performs equally well or close to it from both sides of the plate.
Understandably, there is an element of comfort involved in always looking at a right-handed pitcher from the same angle. But even comfort, at some point, is trumped by a large drop-off in production. And that threshold comes when there is a 10% or greater difference between the OPS in one batter's box versus what the OPS is in the other.
After looking at the list of active switch hitters, I weeded out the ones who had not accumulated, since 2002 up to however many at-bats they have had this season, at least 500 at-bats as a right-handed better and 500 at-bats as a left-handed batter. When that was completed, I looked at their splits over the aforementioned time span and then took the percent difference between their higher OPS and their lower one. These are the hitters with whom switch hitting does not agree.
As LHB: .424 OBP/.592 SLG/1.016 OPS in 1,789 at-bats
As RHB: .392 OBP/.425 SLG/.818 OPS in 543 at-bats
Lance Berkman's inclusion on this late is certainly no indictment on his talent. His career line of .302 BA/.414 OBP/.560 SLG is impressive any way you look at it and he is one of the elite players in MLB right now. However, an interesting question to ask is how good those numbers would be if he did not consider himself a switch-hitter and stuck only to the left-handed batter's box. They probably would not be any worse.
The most glaring difference between these two splits is with what little power Berkman hits with from the right side. His OBP is similar and so is his BA, but for a power hitter like Berkman to only slug .425 from the right side is embarrassing. The only thing more embarrassing is that he continues to bat right-handed when doing so makes him 80% of the hitter he is from the left side of the plate.
As LHB: .369 OBP/.326 SLG/.694 OPS in 1,761 at-bats
As RHB: .389 OBP/.483 SLG/.872 OPS in 656 at-bats
Castillo, like Berkman, has a 20% decrease in production, but unlike Berkman, Castillo hits better from the right side of the plate than he does from the left side. The problem is he is not a stellar hitter from either side.
As a leadoff hitter, Castillo's main job is to get on base, which he does well from each side of the plate. In the right-handed batter's box, at least he couples that with a .483 SLG. One cannot say the same thing about his life as a lefty batter. It is not simple feat for a player to have a slugging percentage lower than his on-base percentage, but Castillo has found a way to do it.
The Minnesota Twins would be well-advised to build an invisible dog electric fence around the lefty's batter's box, attach a collar around Castillo's neck, and shock him until he learns he is no longer allowed to bat left-handed.
As LHB: .375 OBP/.437 SLG/.812 OPS in 1,369 at-bats
As RHB: .310 OBP/.350 SLG/.660 OPS in 586 at-bats
Brian Roberts burst on the national scene last year when he posted splits of .459 OBP/.726 SLG/1.185 OPS, .440 OBP/.569 SLG/1.009 OPS, and .407 OBP/.534 SLG/.942 OPS over the first three months of the season. He cooled off during the course of the year, but still finished up the season with a very respectable line for a lead-off hitter of .387 OBP/.515 SLG/.903 OPS.
Now he is notorious for another reason, namely being a poor switch hitter. With a 19% drop-off in OPS, there is really very little reason for him to continue hitting from the right side of the plate. Not only does Roberts' OPS suffer when he bats righty, but his batting average also takes a precipitous drop from .305 BA to .237, a decrease of .68 points.
The fact that Roberts is just an average defensive second basemen makes the disparity between the sides of the plate even greater. A player whose offensive ability is his most important contribution to the team should not continue to hurt the team by batting so poorly when facing a particular handed pitcher.
As LHB: .345 OBP/.362 SLG/.708 OPS in 875 at-bats
As RHB: .380 OBP/.487 SLG/.867 OPS in 534 at-bats
Bobby Kielty has the most equal split between how many at-bats he has had from each side of the plate, but he also has one of the more unequal OPS splits since he is 18% better, in terms of OPS, from the right side than he is from the left.
As is the case with most switch-hitters who do not hit similarly from both sides of the plate, Kielty has a wide power imbalance. Not only does he have a slugging percentage .125 points higher from the right side, his isolated power difference (slugging percentage minus batting average), a better indicator of how much true power a player has, is a hefty .71.
Perhaps his blinding red hair keeps the Oakland A's and himself from realizing right-handed at-bats are probably the way to go for him.
As LHB: .343 OBP/.468 SLG/.811 OPS in 1,400 at-bats
As RHB: .304 OBP/.381 SLG/.686 OPS in 493 at-bats
Carl Everett may not believe in dinosaurs, but he should believe that his 15% disparity in OPS is an indicator that switch-hitting is hurting him more than it is helping.
Or since OPS is not found in the Bible, does that mean it doesn't exist?
Although Everett is 7 at-bats shy of the 500 at-bat requisite mark, he could hit seven straight homers from the right side and still not bring his OPS percent difference below 10%.
As LHB: .357 OBP/.383 SLG/.739 OPS in 1,124 at-bats
As RHB: .357 OBP/.509 SLG/.866 OPS in 501 at-bats
There was probably a time when Mark Bellborn thought switch-hitting was a good idea and that he was going to ride it to the major leagues. If so, that day is over, and he should look at the 15% drop-off in OPS and realize it for himself. Since he probably will ignore his split, he will spend the rest of his career in a batter's box where his isolated power is .99 points lower than it is from the right side.
Would he be an above average hitter if he concentrated on one side of the plate? We will probably never find out.
As LHB: .348 OBP/.438 SLG/.787 OPS in 1,453 at-bats
As RHB: .384 OBP/.528 SLG/.912 OPS in 572 at-bats
Jason Varitek, captain of the Boston Red Sox, may be a surprise addition to this list, but there the numbers do not lie, and they say there is a 14% drop off in OPS. As captain, one can surmise it is Varitek's duty to do all he can to help out his team. Well, one thing he could do to help out the Sox would be to focus solely on his right-handed hitting and see if his numbers improve.
Otherwise, he will just continue to tease the Red Sox Nation with his displays of power as a right-handed batter.
As LHB: .375 OBP/.463 SLG/.838 OPS in 1,377 at-bats
As RHB: .318 OBP/.415 SLG/.733 OPS in 559 at-bats
Carlos Guillen has played for two teams over the past five seasons, but one thing he brought to Detroit from Seattle is his inability to match his left-handed production on the right-handed side of the plate. While the gap between his two OPS's is not as glaring as some of the others on this late, there is no denying the 12% decrease.
There is no huge discrepancy in any one category of Guillen's splits, but the accumulation is enough to warrant him putting his switch-hitting career on hold indefinitely.
As LHB: .357 OBP/.434 SLG/.791 OPS in 1,582 at-bats
As RHB: .386 OBP/.493 SLG/.879 OPS in 515 at-bats
Ray Durham barely made this list, coming in at a 10% differential, but working under the logic that what he did over the past 2,097 at-bats is probably indicative of his split for his career, maybe his career numbers would be higher than they are.
It is probably too late to convince him to stop his switch-hitting now; maybe someone should have told him to stop when he first began.
As LHB: .339 OBP/.433 SLG/.772 OPS in 1,377 at-bats
As RHB: .287 OBP/.346 SLG/.633 OPS in 492 at-bats
% Diff. 18%
As LHB: .350 OBP/.402 SLG/.753 OPS in 1,225 at-bats
As RHB: .337 OBP/.327 SLG/.664 OPS in 490 at-bats
% Diff. 12%