In an effort to find to bring a new angle to the routine nature of season previews, last year New English D ran a season preview series based on the team’s nine most pivotal players. We be called the series “2016 Bellwethers,” broke down the players whose 2016 direction would indicate where the Tigers were heading. Due to a solid response, the series is back for 2017. Keep in mind this is not a series about the most important Tigers, but rather the Tigers with the widest range of possible outcomes. You won’t see Miguel Cabrera featured, for example, because of his steady dominance of the league. Enjoy. | #9: James McCann and Alex Avila | #8: Victor Martinez | #7: Whoever Plays Center Field |#6: Jose Iglesias | #5 Jordan Zimmermann | #4: Daniel Norris

Nick Castellanos has been coming together in pieces. He made his debut in 2014, improved his defense in 2015, and added power in 2016. He’s by no means a good defender and his approach is still very tenuous, but he showed last year that you can provide some value if you post a .212 ISO.

It’s not quite that simple, however. You could look at Castellanos’ 110 games and 1.9 WAR and indicate that if he hadn’t taken that pitch off the hand, we’d be talking about a 2-3 win player. But that isn’t exactly right because the best part of Castellanos’ season was the beginning. Or to put it more clearly, he was terrible in June. From 5/28 to 6/26, Castellanos had 123 PA and posted a 66 wRC+. Prior to that it was 158 (179 PA). After June 26, it was 115 (145 PA). There’s no magic to it, everyone has good stretches and bad, but if you wanted to make the case that Castellanos’ performance tapered off as the year went on, you could do it.

Castellanos is young, newly 25. People have been marveling at his hit tool for years and the power arrived last season. No one is expecting him to be Brooks Robinson, but his improvement from horrible to merely below average is legitimate. The question is if Castellanos is going to be a 110-120 wRC+ guy or something more. Don’t get me wrong, a 115 wRC+ and non-atrocious 3B defense will get you major league work, but if Castellanos is going to live up to the promise of “All-Star Third Baseman” that we heard from certain scouts, he needs to take a step forward.

The biggest room to grow is his approach. He’s been much better when he’s been able to lay off breaking balls low and away. If you come inside with fastballs he will make you pay, but he’s still too aggressive elsewhere in the zone. You can survive as a major league hitter with a 6 BB% and 25 K%, but you have to have good power or a good glove. To excel with a 6 BB% and 25 K%, you have to crush the ball. I think the easier path is become an 8 BB% and 21 K% guy, but we’ll see if that’s in the cards.

Castellanos is third on this list because he has the most two-sided range. He could easier regress to his 2015 value or take a step forward into something resembling a fringe all-star. I think both are realistic options. Was the power fluky or can he improve his approach? He’s young and a hard-worker, so the upside is definitely there.

The Tigers are going to be without JD Martinez for a spell, and there’s some uncertainly surrounding Victor and Upton at the plate. Castellanos can step up and give the Tigers a boost, or he can fall back and leave them wondering what their long term plan should be at the hot corner.