With Taveras, it is his historic walk aversion that makes him a dicey player. If he walked 10% of the time instead of 5%, then he'd be a fine player. This is also a bit of a hunch due to small numbers, but there is a small pattern in his career of starting the season with an acceptable OBP, a bit of SLG, and then falling apart. Perhaps he loses discipline, but his (PAs) BA/OBP/SLG by month over his career is:
Mar/Apr (482) .270/.333/.387
May (516) .259/.304 /.310
June (441) .277/.298 /.351
July (396) .285/.326 /.333
August (460) .294/.341 /.330
Sep/Oct (270) .259/.309 /.292
In March/April, he walks 8.5% of the time, but then, he becomes more of a hacker and his OBP tails. the OBP is mostly BA driven by May.
Historically, he does not have any split on SLG (he stinks against righties as much as lefties). If anything, he gets on a bit better against righties (OBP v. LHP - .309; v. RHP - .324). Here is his // line over the last three full seasons and career v. LHP, and here is also Harris's:
Taveras v. LHP
2007 (99) .371 / .417 / .471
2008 (143) .266 / .321 /.313
2009 (113) .219 / .245 /.257
Career (668) .262 / .309 /.328
Harris v. LHP
2007 (56) .191 / .291 /.234
2008 (113) .240 / .327 / .450
2009 (45) .121 / .356 / .212
Career (381) .200 / .286 / .301
Hopefully, I've minimized the transcription errors. Easy enough to say, if he can repeat 2007, then we have a find. 2007 marked his first year of two with the Rockies, then he went to Cinci and here. Maybe there is a bit to the line from Taveras and Eckstein about getting back to how he hit instead of forcing him to be a slappy GB guy (although his lowest GB% was 2009, his worst year). I don't know what sort of hitting coach changes there were or things like that (I'm too lazy to look them up right now). He probably deserved better luck in 2008 with the rockies when you look at his LD% (career best) and GB% (same as 2007), but his BABIP dropped .034 below his worst prior year (and .074 from 2007).
I'm guessing the Nats are saying, take a mulligan on 2009, and get back to what you were doing before. We can use you to cover up for Willie's weakness (LHP) and, if you take a walk or two, get some value and restore your reputation as a major leaguer. This does look like a stat guy call. And yes, everything I did is from Fangraphs, so that Rotowire crack might be spot on.