Scouts remain bullish on d'Arnaud because he has the potential to contribute offensively and defensively like few backstops can. That's what makes him the game's top catching prospect, even if Jonathan Mayo disagrees and vouches for Austin Hedges of the Padres.
The 24-year-old d'Arnaud stands out the most for his prowess at the plate, and he keeps getting better and better. A career .286/.347/.476 hitter in the Minors, he has boosted his OPS from .726 in high Class A to .906 in Double-A to .990 in Triple-A. d'Arnaud's best pure tool is his above-average right-handed power, which he generates with a combination of bat speed and strength, and he could smash 20 homers annually in the Major Leagues.
d'Arnaud shows a feel for hitting as well, and his compact swing and all-fields approach should translate to solid batting averages as well. He could stand to draw a few more walks, but he has made progress with his plate discipline as he has risen through the Minors. d'Arnaud very well could produce .275/.340/.500 lines year in and year out in the Major Leagues.
Hedges is no slouch with the bat, either, but he doesn't have d'Arnaud's offensive upside. His .768 OPS last season in the high Class A California League was fairly pedestrian considering it came in a notoriously hitter-friendly circuit, and he recorded just a .566 OPS after an August promotion to Double-A (granted, a small sample size). Hedges projects to be more of a .260 hitter with maybe 15 homers per year in the Majors.
To Hedges' credit, he's probably the best all-around defensive catcher in the Minor Leagues. But d'Arnaud also gets the job done behind the plate, with his throwing and receiving giving him two more solid tools.
d'Arnaud's defense took a significant step forward in 2011, when he was the Double-A Eastern League Most Valuable Player while playing for New Hampshire manager Sal Fasano. Fasano, who caught 11 seasons in the big leagues, helped d'Arnaud improve his catch-and-throw skills. He has cut down 34 percent of potential basestealers in the Minors over the past three seasons.
The only knock on d'Arnaud -- besides his well-below-average speed, which doesn't matter with a catcher -- has been his inability to stay healthy. He had back problems in 2010, tore a knee ligament trying to bust up a double play in 2012 and missed most of the first half of last season after fouling a ball of his left foot and breaking it. The good news is d'Arnaud's medical history appears to be more a case of repeated bad luck rather than chronic injury.
If not for the broken foot, d'Arnaud likely would have taken over the Mets' catching job long before August. Now that he has it, he won't give it up for a while and should become New York's best backstop since Mike Piazza.
Jim Callis is a reporter for MLB.com and writes a blog, Callis' Corner. Follow @jimcallisMLB on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.