From 2006-2011, Chris Iannetta stepped to the plate 1733 times in a Rockies uniform. No other catcher in Rockies history is within 540 plate appearances of Iannetta. So when Iannetta was traded for Tyler Chatwood, who was three years old during the Rockies inaugural season, in the offseason, it truly meant a changing of the guard.
Wilin Rosario was the man that made Iannetta expendable, but Rosario's regression in 2011 in AA gave reason for concern. Rather than bringing in the veteran backup, the Rockies elected to sign Ramon Hernandez, who was coming off consecutive 112 OPS+ seasons, to a two-year, $6.4million deal. Hernandez was to be the starter for 2012, with Rosario getting the playing time his performance deserved.
Instead, it was Hernandez who fell completely flat in the bright lights of Coors Field. The veteran hit a pathetic .217/.247/.353 during an injury-ravaged campaign that included hand soreness, a hand strain, a bruised shoulder, a bruised elbow and a ruptured hamstring tendon in his thigh that required surgery. In all, Hernandez missed 71 games due to injury.
The window was wide open for Wilin Rosario, and he was up to the challenge, becoming the most profitable fantasy catcher in MLB. He showcased his power by averaging the fifth highest average flyball distance, setting a Rockies' rookie record for home runs, and posting a .260 ISO (which would make his top 10 in MLB if he qualified in PAs). He also hit some glorious mammoth home runs. Just watch them.
Of course, watching videos of passed balls and wild pitches wouldn't be so fun. Rosario allowed a wild pitch to get by him once for every 25.3 batters that came to the plate, truly amazing given wild pitches don't count when no one is on base. His 21 passed balls not only led the league, but were more than every MLB team except the Mets.
Surely some of this blame should fall on an inexperienced Rockies pitching staff. While Rosario's receiving is decidedly unacceptable, Rockies' pitchers had an ERA of a half run better with Rosario than Hernandez, Wil Nieves or Jordan Pacheco. Passed balls lead to unearned runs, but Rockies pitchers allowed just 0.35 unearned runs per nine innings with Rosario, also the lowest of the four catchers.
While this indicates a likely systemic problem with the pitchers, it absolutely does not excuse Rosario's issues. Matt Klaassen of Fangraphs and The Score published his catcher defense ratings for 2012 last month. While Rosario ranks very favorably at catching would-be base-stealers and avoiding fielding errors, he committed too many throwing errors and cost more runs with his blocking than any two catchers combined. The result? Rosario ranked 116th out of 116, costing the Rockies more than one win on his defense alone.
Rosario showed the ability to adjust to Major League pitching while standing beside the plate, improving his approach and discipline as the season went on. An absolutely critical storyline for 2013 is whether Rosario can improve his ability to adjust to Major League pitching from behind the plate.
Without marked improvement, Rosario won't last as an every day catcher. Not only does being a sieve rather than a backstop directly cost runs and games, but pitchers need to have confidence in their receiver to throw certain pitches. And does he have the intangibles a young staff needs? Wilin played first and third base in 2012 as a bit of a warning of a possible change. Hopefully, that is the last time he plays there.