Every year there are – at most – a handful of teams that go into the season with the luxury of knowing that they will almost certainly make the playoffs if everything goes as planned (on their end). Teams in that situation wind up with different needs and different priorities than the vast majority of their competitors.
Let me explain for a second, though this might get a little technical… There is a huge, huge amount of randomness inherent in baseball. Even if nobody gets hurt, a team can easily wind up 5 or more games off their “true talent” projection based on pure luck alone. A .300 hitter has a 30% chance of getting a hit in any given at-bat, but that isn’t necessarily going to lead to getting hits in exactly 30% of his 600 at-bats during any given season. And he’s not going to get hits in exactly 30% of the times when it counts the most. You could wind up scoring 50 more runs, or 50 fewer runs, than you expected without actually fielding a better team or a worse one (though people would start to think you stunk if you had some prolonged awful luck). So, when we say that the Tigers might project as a 92-win team based on raw talent what we really mean is that there is some kind of “probability distribution” for Tigers performance centered on 92 wins. The same goes for the 85 win Royals, or the 83 win White Sox. If you estimate those whole “probability distributions”, you can estimate the odds that the Royals will finish enough above their 85 AND the Tigers will finish enough below their 92 that the Royals will finish above Detroit to take the AL Central. In a nutshell, that’s how the stat guys that make the Vegas odds predict the likelihood that a team will make the playoffs or win the World Series (as does Diamond Mind and others outside of the gambling industry).
OK… now for why this should matter: teams like the Royals, White Sox, etc… have fairly long odds to win the division because their expected win total (based on true talent) is so far behind Detroit. The Tigers, on the other hand, have not just relatively good odds but very good odds. Teams like the White Sox or the Royals ought to be gambling whenever possible, to try to (whether or not this does a lot to increase their “average” win total) increase their chances of winning 90. I’d say that the Royals have done exactly that – the team isn’t just better than before, they’re full of guys that could be either great or awful.
Among the division leaders, some have basically the same situation as the Royals but with more cause for optimism. That is to say: if they win their “expected total” somebody will probably get lucky enough to beat them, even if nobody else would do that without an inordinate number of breaks going in their direction. I’d say that last year’s Yankees and Braves would fall in that group. The Tigers are in the other group: if they actually win 91 or 92 games, it’s pretty darn unlikely that somebody else in that division would play so far above their head as to win 94 and beat them out. Possible, but unlikely. Whereas the biggest risk to the 2013 Dodgers is probably some other NL West team playing really well, the biggest risk to the 2013 Tigers is that they not only underachieve (as in 2012), they underachieve so much that an 86-win Kansas City team takes the division.
As a result, the critical thing for the Tigers right now is to make sure they have a spare just in case the wheels come off. And, it isn’t possible for the team to “insure” against bad breaks on balls in play or bat clutch hitting/pitching, etc… but it is possible to insure against injury (Victor Martinez) or catastrophic ineffectiveness (Ryan Raburn). Obviously, if Justin Verlander makes 5 starts before he feels some stiffness in his shoulder there is absolutely no way to prevent the rotation from taking a big hit. But… wouldn’t you rather replace him with Drew Smyly than Casey Crosby? Putting in Smyly could make the Tigers an 88-win playoff team (again). Putting in Crosby could make the team an 84-win failure.
I’d say the 6th starter question is by far the most important insurance policy that the Tigers need to have in place, but not the only one. IF the Tigers make no moves from now on – which means they not only keep Porcello and Smyly to give rotation insurance but they also keep Brennan Boesch and Ramon Santiago – insurance policies for most positions are about as good as you’re likely to get (without a team custom-designed for that purpose). The most glaring vulnerability would appear to be center field: nobody else that the Tigers are likely to have can play decent center and hit his weight – including Quintin Berry. Dirks could do it – but he shouldn’t. The same goes for Torii Hunter, they don’t have the necessary range. One major vulnerability might not be that bad, most teams have one or more, but all that assumes that the Tigers do not make any salary dumps (of Boesch, Porcello or Santiago) – so that they would actually have a backup plan if they needed a starter, a corner outfielder, a third baseman, a designated hitter, etc… If those guys go (and we keep hearing rumors that the Tigers would like to get rid of all of them) the Tigers become a team with an extreme lack of organizational depth – largely because of a lack of even middling prospects in AAA.