Stats report: What's wrong with Robinson Cano?

Today's statistical report is brought to you by the National Association of Junk Dealers, because that's what Robinson Cano is starting to see a lot of at the plate.

Hold on, let's back up.

The Seattle Mariners are paying Cano to be a superstar. They need him to be a superstar. With a $24 million salary in the second year of his 10-year contract, he's the fourth-highest paid player in the American League, behind Justin Verlander, Josh Hamilton and Felix Hernandez. Through 37 games, he's given the Mariners these uninspiring totals: .253/.294/.353, one home run, 11 RBIs, a .194 average with runners in scoring position. The Mariners are scuffling along at 17-20, and Cano struggling is one big reason why.

So, what's going on?

Before we analyze, it's worth noting that Cano also got off to a slow start last season, at least in the power department. He had just two home runs through June 10. The big difference is he was hitting .333 and driving in runs, so he was at least productive even though he wasn't hitting the ball out of the park. Still, Cano finished with 14 home runs, well below the 28 he averaged the previous five seasons with the Yankees. (That wasn't all a result of Safeco Field; nine of his 14 home runs came at home and Safeco is actually pretty fair to right field, where the ball carries better than it does to left.) The other concern so far is that his strikeout rate is up and his walk rate is down. Add it up and it's a legitimate concern.

OK, so here's what's wrong with Robinson Cano: He's not hitting offspeed stuff. Check out two heat maps with his batting average against curves/sliders/changeups/splitters in 2013 and so far in 2015:

Here are his overall numbers against those four pitches over the past five seasons:

2011: .294/.301/.560

2012: .333/.377/.598

2013: .316/.358/.608

2014: .279/.298/.466

2015: .194/.206/.323

From 2011 to 2013, Cano was maybe the best hitter in the game against offspeed pitches. In 2013, he ranked second in the majors in wOBA (a sum of a hitter's offensive stats scaled to on-base percentage) to Chris Davis; in 2012, he ranked first; in 2011, he ranked second to Miguel Cabrera. His remarkable balance at the plate and ability to hit to all fields allowed him to hang in against breaking balls.

Those numbers slipped last year and have slipped even further this year, with the poor results most acute against left-handed pitchers (who throw a lot of breaking balls) to left-handed batters. Look at his overall numbers against southpaws:

2011-2013: .279/.339/.426

2014: .294/.356/.390

2015: .162/.162/.270

So the basic story: In 2014, his power was down; in 2015, everything is down.

But is it just struggles against offspeed stuff? Not necessarily. In looking through his numbers, Cano has never been a great fastball hitter. From 2011-2013, he ranked 96th in the majors in wOBA against fastballs, sandwiched between Nate Schierholtz and Desmond Jennings. In 2014, he ranked 44th, with a .377 woBA against fastball. So far in 2015, he ranks 112th with a .338 wOBA. His strikeout rate against fastballs is 15.8 percent, up from 6.9 percent a year ago.

Speculating here: Is he cheating against the fastball, either trying to jack one out or -- scary thought for Mariners fans -- because the bat speed is slowing down? And is cheating against the fastball leaving him vulnerable to the breaking ball?

One good sign: His well-hit average -- the percentage of all plate appearances ending in a ball defined as hit hard -- is basically the same as it was last year (even with more strikeouts), .191 to .182. So there's been some bad luck going on here as well.

Still, there are some red flags here. Cano's track record suggests this is only a long slump. At 32, he shouldn't be declining yet. With nine years left on his contract, he better not.