I recently came across an interesting new site co-founded by writer Aaron Wright. The site, ArmchairGM, grants fans a medium through which they can voice their thoughts and opinions online. It's not constricted to baseball, either, and is relatively easy to use. In fact, I posted an entry myself, which I have included here as well. Please check out the site if you have not yet done so.
For the most part, platoons aren't employed nearly as often as they should be. Last season, for example, Eric Hinske totaled 88 at-bats against left-handed pitchers last season. In those at-bats, he posted a putrid line of .170/.215/.330. Against right-handed pitchers, on the other hand, he posted a much better line of .283/.358/.452 in 389 at-bats. To be fair, manager John Gibbons did bench him against a good number of lefties, but it's inexusable -- not to mention very detrimental to the team's success -- to grant him even 88 at-bats against them. As a result, it's wise to employ a platoon when a roster includes hitters who historically post contrasting split totals.
Obviously, the manager must take various factors into account before employing one. Not only must he take offensive production into account, but also defense and, perhaps even more importantly, how the players and the fans will react to it. Often, a platoon has a rather negative stigma associated with it; players may view it as a sign of disrespect, and fans may view it as a sign of weakness. If the employment of a platoon were to heighten production significantly, however, the manager should be able to find a way to overcome those problems.
As of now, it would likely be in the best interests of the Blue Jays to employ platoons at three positions: catcher, left field, and right field.
Catcher:
In this case, a platoon would be benefecial because Molina absolutely crushes left-handed pitching but is very vulnerable against right-handed pitching. On the other hand, Zaun has historically performed equally well against both. It must also be noted that his OPS is much more OBP dependent than Molina's. This is important because it results in more runs created. It's easier to increase .001 point in SLG because it functions on a scale of 4.000 vs the OBP scale of 1.000, so one point of OBP is more valuable than one point of SLG (of course, there are much better explanations and studies done on the matter, but that's just a quick approach based on common sense). Secondly, Zaun's significantly higher OBP can be attributed to his high walk rate. Molina's OBP, on the other hand, is extremely dependent on his batting average, which tends to fluctuate much more than a player's walk rate. With that said, Molina projects to get the brunt of the playing time this season, partly because of his reputation and high-priced salary.
Left field:
Evidently, this platoon is almost necessary. Catalanotto simply isn't productive against left-handed pitchers, while Johnson is noticeably better against right-handed pitchers. John Gibbons will almost surely employ this platoon to begin the season, and it they would be particularly productive at the top of the lineup in place of the incumbent, Russ Adams.
Right Field:
Due to the additions of Troy Glaus and Lyle Overbay, Hinske quickly became a man without a position. As a result, he's testing the outfield waters (grass?) as a potential platoon partner with the continually underperforming Rios. Interestingly, Rios's production actually increases against right-handed pitching, but that doesn't render this platoon unwise. One major concern, however, is Hinske's defense in the outfield. He was an subpar defender at third base, but that doesn't necessarily mean it'll translate into the outfield. It's definitely something to keep an eye on throughout the season.
Although they have yet to be fully embraced by managers and fans alike, platoons certainly do have their merits. Even in an economic sense, they're very beneficial to the team that employs them. For instance, last season, the Phillies' employed a highly effective centerfield platoon of Kenny Lofton and Jason Michaels, who combined to produce 28 win shares, the second highest total among all NL centerfielders. The best part, however, is that their combined salary was $3,740,908, a definite bargain for the production they provided.