Some good news about Eric Hosmer

After a strong rookie season in 2011, Eric Hosmer's sophomore campaign has been one of the bigger statistical disappointments of 2012. Entering Sunday's action, he's hitting .234/.304/.366. That .670 OPS ranks 130th of 146 qualified regulars and represents a 129-point drop from 2011's .293/.334/.465 line. His home run on Thursday was his first since June 25, ending a 32-game homerless drought.

"It’s been a tough year for me," Hosmer told the Kansas City Star a few days ago. "It really has. In the beginning, I hit the ball well and had nothing to show for it. I really do believe I was swinging well at that time. But it built up and built up ... I was telling myself nothing was wrong, but you look at the stats ... and, obviously, the numbers aren’t where you want them to be. I felt if I was doing my part -- not that I’m a numbers guy, but if my numbers were there -- I’d be helping this team more."

Hosmer's struggles are even more surprising in light of a big spring training that raised expectations for the 22-year-old first baseman. "Watching him in spring training, I thought he was going to hit 35 home runs this year," teammate Jeff Francoeur said. "I still see Hos having a great career. Everybody goes through ups and downs."

In some ways, the rookie exploits of Mike Trout and Bryce Harper have spoiled our expectations for young players. Keep in mind that Hosmer is still very young; most 22-year-olds are still in the minor leagues. Nonetheless, you do like to see a young player improve, not regress.

Hosmer's Baseball-Reference Wins Above Replacement stands at -0.4. (For the second straight season, his defense -- despite good reviews -- grades out as below average, which isn't helping.)

That's the bad news. But here's some potential good news for Royals fans. Since 1950, 24 players in their age-22 seasons have accumulated 500 plate appearances and finished with 0 WAR or less. While there are some forgettable names on that list -- Enzo Hernandez, Charlie Spikes, Peter Bergeron -- there are also three Hall of Famers in Ron Santo, Nellie Fox and Bill Mazeroski.

OK, Fox and Mazeroski are more glove-first Hall of Famers. But the list also includes Dale Murphy, who hit .226/.284/.394 at age 22. Murphy, like Hosmer, was 6-foot-4, so it's easy draw a comparison there, although Murphy was in his rookie season. Another intriguing name on the list is Prince Fielder, although much of his negative value came from his defense. He hit .271/.347/.483 at age 22 (his rookie season) -- and then exploded with a 50-homer season at age 23.

If we focus strictly on hitting, Hosmer's OPS+ is 83. The list of the 23 22-year-olds since 1950 who finished with an OPS+ between 80 and 90 includes Tommy Davis, Ryne Sandberg, Robin Ventura, Jose Reyes and Adam Jones.

It's hard to evaluate Hosmer's season. His walk rate is slightly improved his rookie season (8.7 percent to 6.0 percent) and he doesn't strike out excessively. His BABIP -- batting average on balls in play -- is just .256 compared to .314 as a rookie. So there may be some bad luck there, but he's also hitting a lot more ground balls than last year. With just 29 extra-base hits, it's clear he's not driving the ball.

What to expect moving forward? I have no idea. It's a strange regression, unless there is some unknown injury involved that Hosmer hasn't let on about. I wouldn't write off his star potential just yet, even if his season has been a disappointment.