Posted by Bill Baer on Sunday, March 8, 2009 at 1:30 am

My recent posts comparing the Mets and Phillies at Crashburn Alley sparked an interesting debate at Baseball Think Factory, which brought something to light for me: Mets prospect and starting left fielder Daniel Murphy is extremely over-hyped. The Bill James projection system has Murphy putting up an .849 OPS in 2009 and no one seemed to sneeze at that during our debate at BBTF.

Bill Madden of the New York Daily News compared Murphy to Don Mattingly. No, I didn’t make that up:

In a lot of ways, he reminds you of Don Mattingly at the same age. Mattingly, too, was primarily a gap hitter when he arrived in the big leagues in 1983, and there were questions as to whether he would hit for enough power at first base. In the spring of 1984, then-Yankee manager Yogi Berra declared that Mattingly would be his “swing man,” alternating between left field and first base. “I don’t know how many homers he’ll hit,” Berra said, “I just know he can hit.”

When I suggested to Mets manager Jerry Manuel Friday that there were seemingly a lot of similarities between Murphy and Mattingly, his eyes widened.

“That’s quite a comparison,” Manuel said, “but you’re right insofar as the tremendous work ethic, that classic (lefthanded) swing and the willingness to play anywhere. When it comes to the power with Daniel, that’s what you hope happens – just like it did with Mattingly. I think it will come because he’s going about everything in the right way. He’s shown me he can be the perfect guy for this club, fitting right into the core.”

Quite a comparison, indeed!

For the record, the Bill James projection system is the only one that sees Murphy being so productive offensively. CHONE has him at a .746 OPS, Marcel an .825, ZiPS a .746, and MattS of The Good Phight and Statistically Speaking has him at .770.

My question is: What has Murphy done to justify a projection of an .850 OPS in 2009?

He had 151 plate appearances last year with the Mets in August and September with a slash line of .313/.397/.473. Not bad at all. But it is only 151 plate appearances — a small sample size — so they should be taken with a grain of salt.

Murphy’s Minor League career isn’t even terribly impressive. In 957 at-bats, Murph’s got a slash line of .290/.352/.444. Most of his playing time came in 2007 in A-ball with St. Lucie (.768 OPS) and last year in AA Binghamton (.870 OPS).

He had a good walk rate in his limited Major League experience at about 12%; it was 7.7% with St. Lucie and 9.8% with Binghamton. His strikeout rate with the Mets was high though, at 21.4%; it was 12.2% with St. Lucie and 12.9% with Binghamton.

Those Major League peripherals are a bit wacky simply because of the small sample size we’re dealing with. It’s likely Murph’s true Major League walk rate — at least for the near future — is somewhere around 8% and his strikeout rate is around 13 or 14%. But what really jumps out at you about his brief Major League success is his unsustainable line drive percentage: 33.3%. The average LD% is around 20%.

Because he hit a lot of line drives, he was very fortunate on balls in play, reflected by his BABIP of .386. If we assume he’s a normal baseball player with a LD% around 20% give or take a couple of percentage points, we would expect his BABIP to naturally be as many as 50 or 60 points lower to the .320-.330 area. As such, his true level of production isn’t the .373 wOBA he had last year nor the .368 Bill James predicts for 2009; it’s likely much closer to the .330 that Marcel predicts.

If you don’t believe that his LD% will fall, know that of hitters with at least 400 plate appearances last season, Jamey Carroll led the way at 27.3%. Andre Ethier was next at 26.6%.

Murphy’s production last year is unsustainable. Even if we assume that he naturally hits a lot of line drives, say 24%, he’s still going to have a proportion of about 9% of his line drives (which dropped in for hits last season) finding defenders’ gloves in 2009.

Even if Murphy is as good as Bill James says he will be, there’s no reason to project that with the information at hand.