Is Starlin Castro a franchise player?

In early May of 2011, Starlin Castro was hitting over .300 and Sports Illustrated put the Cubs shortstop on its cover, writing "21-year-old Cubs phenom grows up before our eyes."

The Cubs just signed their now-22-year-old shortstop to a seven-year, $60 million extension that takes him through 2019 and also includes an option for 2020 at $16 million. I'm not sure it's really worth breaking down the parameters of the deal. Sometimes, we get too caught up in the money. Whether Castro is going to be worth $45 million or $60 million or $80 million over the life of the contract isn't that big of an issue; a few million here or there per year isn't a major factor to an organization like the Cubs. Bottom line: Castro is a good player and unless he blows out both knees it should be a good contract for the Cubs.

No, the more important question: Is Castro a franchise player? Is he the kind of player who can be the best player on a playoff team? My feeling is he isn't. I know many will disagree with me; after all, Castro is just 22, already led the league once in hits and owns a .296 career average. His defense, once questioned, has by all accounts improved substantially, to the point that there are no longer questions that he'll remain at shortstop.

My concern is that he hasn't really improved at the plate. His on-base percentage is 36 points lower now than it was his rookie season. After a good start to 2012, he's hit just .248 over the past three months. Since he doesn't walk much, he needs to hit .300 to have offensive value.

The common analysis would be that he's just 22 and will improve. That's generally true, but it hasn't happened in three seasons with Castro. His walk percentage is actually lower than it was his rookie year and his strikeout percentage is slightly higher. He has more home runs, but his extra-base hit percentage has held steady at 28 percent. Not all 22-year-olds improve.

Look, he's a good player and there's certainly a chance he could become a great one. Maybe Castro follows the Robin Yount path; Yount reached the majors when he was just 18, but didn't really become ROBIN YOUNT until his seventh season, when he was 24. In fact, it's kind of scary how they profile as similar players: As young players, neither walked much but both were good contact hitters. They had speed but not blazing speed. Yount made 44 errors as a 19-year-old. Castro is still error-prone (29 last year, 21 this year).

So that's a best-case scenario. I hope it happens. And then the Cubs just need to find five or six more stars.