When the Mets called Daniel Murphy up on August 2, 2008, he had played just one game above Double-A and spent just two-thirds of a season above A-Ball. It didn't seem to matter much, as Murphy hit .313/.397/.473 with a wOBA of .373 and .9 WAR in just 151 plate appearances. A third-baseman in the minors, Murphy looked a bit clumsy in left field but his defense still rated above average by UZR and +/-.
Prior to his late-season stint with the big club, Murphy wasn't an especially well-regarded prospect in the Mets' organization. John Sickels of MinorLeagueBall.com considered him the 18th best prospect in the system, grading him out at a C and placing him between the not-quite-phenomenal Hector Pellot and Ezequiel Carrera. Nevertheless, Murphy was given a chance to showcase his wares and he made an impression on everyone with his work ethic, his business-like approach to the game, and, most importantly, his seeming ability to actually perform baseball-related tasks competently.
Despite his rapid assimilation into big league life, the red flags were there if you knew where to look. That he had no high-minors experience meant he probably hadn't seen the depth and breadth of breaking balls he would do battle with in the majors. This inexperience didn't seem to affect him much in the final two months of the 2008 season, but the list of middling hitters who have looked like big leaguers for two months is as long as it is unspectacular. The bigger concern about Murphy's early success is that he did so with a line drive rate that seemed, frankly, unsustainable. His BABIP was an unusually high .382, but it appeared to be realistically buttressed by his 30.8% line drive rate. Unfortunately for Murphy, players who can sustain that type of liner rate for a full season are seldom seen; the highest full-season mark since 2006 was Freddy Sanchez's 27.5% that year (FanGraphs will let you go back further, but I doubt you'll find more than a scant few -- if any -- who have exceeded 30%).
Given the confluence of Murphy's luck-aided 2008 and the lack of any better readily-available options, the Mets went with Murphy as their starting left-fielder to begin the 2009 season. His defense looked promising early on, and his bat continued to hold up the lofty expectations placed upon it as Murphy proceeded to hit .324/.373/.800 in April, buoyed by a .339 BABIP. Things fell apart quickly in May, though, as Murphy's slash line plummeted to .176/.278/.353, a larger set of fielding data seemed to expose his defensive maladroitness in left field, and the arrival -- and surprising efficacy -- of 40-year-old Gary Sheffield meant fewer starts for the struggling Irishman.
Carlos Delgado's injury in mid-May facilitated a move for Murpy to first base, whose unfamiliarity with the position has nevertheless yielded credible defensive results. Murphy seems far more comfortable at first than he ever did in left, and UZR, notwithstanding the inherent wonkiness of evaluating range at first base, seems to concur with our observations. Offensively, the positional change of scenery has done little for Murphy's impotent bat, which has continued to putter along at sub-replacement levels. He hit .240/.298/.320 in June and .250/.323/.393 in July, and has thus far hit .260/.283/.360 in August. The bad news gets a little bit worse because, while Murphy's offense seems to have plateaued right at the margins of ineptness, his position-relative performance has tumbled even further down the tubes since offense is generally a little easier to find at first base than in left field and the defensive requirements to play the position are a tad lower. The good news, I suppose, is that Murphy's defensive aptitude at the position (compared to left field) probably neutralizes the aforementioned negative positional adjustments.
At this point the Mets have a few options with Murphy. His value would be highest as a second-baseman, but considering how bad he was in left field there's little reason to believe he'd be even serviceable in the middle infield. Further, Luis Castillo is entrenched at second for the next two-plus years, and has been surprisingly decent this season regardless. Murphy played mostly third base in the minors, and with David Wright out for the next two weeks (and hopefully longer), the Mets could move Murphy to third base for a while and see how he fares. At the very least, it doesn't make any less sense than playing Fernando Tatis there in Wright's absence, and any success at the hot corner can only improve Murphy's value to the Mets as a role player or as trade bait.
The last reasonable option, assuming the Mets hold onto Murphy through this offseason, is to start him at Triple-A in 2010 and see if he can improve as a hitter. His defense might be passable, but if he can provide neither league-average power nor plate discipline then he doesn't have much of a future as a big leaguer, with the Mets or anyone else. Quite simply, first-basemen and corner outfielders either have to hit or be ridiculously good at defense (for the latter, see: Chavez, Endy). Right now, Murphy is neither of those things, so he either has to move to a position where his bat will be less of a liability or improve his offense or defense (or both) enough to be a credible utility player. I don't know if I'm especially sanguine about any of those things happening, but for now I would probably move Murphy to third base for as long as Wright is on the shelf and then hope he learns a thing or two in Winter ball. They can then revisit this whole thing in Spring Training and figure out where, and if, Murphy fits into the Mets' plans.