Yadier Molina is falling apart. It’s not his hitting, and it’s not his base running. It’s too early in the season to say much that is meaningful about those skills, which can take months of stats to become reliable.

It’s the Cardinals catcher’s defense that’s a mess. Molina’s pitch framing has collapsed, dropping from third-best in 2013 to 60th in 2015. And the Cardinals are at real risk because of it. Framing was thought of as mythical until researchers found direct evidence for it in how umpires were calling borderline pitches. The idea is simple: A catcher receives a pitch and “frames” it so that the pitch is more likely to be called a strike. In contrast to descriptions of framing as cheating, good framing involves catching the pitch with a minimum of excess motion. In so doing, the catcher offers the umpire a clear view of the ball and thus collects more favorable strike calls.

Since 2008, Molina has been the fifth-best framer in the league. In that time frame, Molina has saved more than 114 runs by flipping pitches that would have been close calls to strikes (worth about 11 wins, in aggregate). Since pitch framing isn’t yet accounted for when sabermetricians project a team’s statistics, Molina’s secret skill helps to explain the Cardinals’ outdoing their projections for the past 10 years and some of their perpetual October success (though to a lesser extent).

But this year, Molina’s framing is no longer even average. Already in 2015, Molina has cost his team about four strikes, while the best framers have gained more than 15. That may not sound like much, but over the course of a season, it could add up to a gap of more than 150 strikes, worth something like 25 runs. In his best year (2013), Molina acquired roughly that many extra strikes for his team, equating to an extra couple of wins per year for the Cardinals. This is no small-sample fluke, either. Unlike hitting and pitching, whose outcomes we still measure in the dozens this early in the season, Molina has seen 800 pitches this year. That sample size is plenty big.

It’s hard to know why Molina has lost his mojo. Some of Molina’s apparent decline may stem not from his own skill diminishing, but rather from other catchers becoming better. As front offices have become convinced of the importance of framing, we’ve seen many light-hitting but exceptional-framing backstops be promoted to full-time roles. Since Molina is always being compared to the average, if the average moves up, it may appear as though Molina is falling.

It’s possible that the physical toll of catching has finally caught up to Molina. Notably, he showed up to spring training about 20 pounds lighter than the weight at which he played for the past 10 years. Molina gave no specific reason for the weight loss when asked, but Adam Wainwright (among others) suggested that it may have been to reduce the wear and tear on his knees.

A decline by Molina, even without cryptic injuries, was not totally unexpected. Although pitch framing doesn’t appear physically demanding, research has shown that there is a clear aging pattern for the skill. Catchers improve when young but decline in their 30s. At age 32, Molina is entering the part of the curve with the most rapid decline.

Still, rapid is an understatement for Molina’s framing slump. Molina’s framing has been falling off of a cliff for two consecutive years, dropping from excellent to above average from 2013 to 2014 and from above average to poor from 2014 to this year. The decline went largely unnoticed last year, as Molina struggled with injuries that limited his playing time.

This year, it’s unmistakable. If you look for two-year declines as large as Molina’s since 2008, there’s only one other player with as many chances who has fallen off as much: Brewers catcher Jonathan Lucroy this year. (Strangely, Lucroy is 28 years old, still relatively young.) Age tends to reduce framing ability, but rarely as quickly as it has in Molina’s case.

Regardless of the cause, Molina’s framing decline affects more than just his own stats. Normally, pitching statistics are much too variable this early in the season to say anything useful. But by learning about Molina’s decline, we may also, in a roundabout way, learn something about the Cardinals’ pitching.

To do so, we can look at the recent history of pitchers who lost great framers. Molina isn’t lost, of course, but his framing skills might as well be. In the past three years, 166 pitchers have stayed on the same team but seen their framers decline in quality by a magnitude similar to Molina’s decline from last year to this year. Those 166 pitchers did 0.76 runs of ERA worse than expected. Compared to the overall population of pitchers in that time (who performed 0.47 runs of ERA worse than expected), the pitchers throwing to worse framers saw their ERAs increase by 0.28 runs.

To any given pitcher, a 0.28 increase in ERA is relatively minor. It could be dismissed as merely bad luck. However, Molina doesn’t just work with a single pitcher — his framing affects every pitcher on the team. His newfound problems will affect each hurler to only a small extent, but the staff as a whole will be dramatically harmed. Over the course of a season, the total effect of the fall from top-tier to below-average framing is something like three wins. In a competitive NL Central, that’s a hefty price to pay.