I present to you a series of triple-slash lines:
The first two lines illustrate the reasoning that many believe is keeping Jesus Montero and his 7 home runs and .900+ OPS in the month of August toiling away in Scranton-Wilkes/Barre. Jorge Posada's line against RHP comes first, and Andruw Jones's demolition of LHP is second. Essentially, the Yankees DH platoon is more than adequate when utilized properly. This allows the Yankees to prevent the inevitable can of worms that would be opened from an actual permanent benching of Posada without being disingenuous ... he really is getting the job done against righties, and Jones is more than doing his part against southpaws.
That doesn't tell the whole story, however. The third line is Russell Martin since his incredible April, which is significantly bolstered by the last week or so. Last is Brett Gardner over the last five weeks, a similar downturn to last season (which was attributed to his injured wrist). Both Martin and Gardner have played nearly every day when healthy, so it may simply be a matter of their bodies breaking down in the heat and humidity of the summer.
How does this apply to Montero? It's simple, really. By calling up Montero the Yankees could rest Martin against tough righties, allowing the defensive stalwart to rest a couple of times per week. Against lefties, Gardner could take the day off, Jones can shift to left, and Montero could shed the tools of ignorance and focus on swinging the stick. All told, this would likely provide Martin and Gardner with two days off per week, rejuvenating them for the stretch run and postseason. It would also allow the Yankees to see what sort of player they have in Montero, both behind the plate and at the dish (while also relieving him of the rigors of catching everyday in the minors).
To provide for this strategy, the Yankees need only send Cervelli down ... a minor loss, if a loss at all. Is this a perfect solution? That's impossible to know without any action - but it certainly seems reasonable and simplistic.