Justin Verlander is not an issue. He's a stud.
Rick Porcello comes with two red flags. One, he's very young (turned 21 in December); two, he had a very low strikeout rate last season. These are both precursors to injury and/or failure.
The conventional wisdom holds that Porcello is different. I have my doubts that he's sufficiently unique to defeat history, as Bob Feller and Bert Blyleven did, and achieve the greatness projected for him.
But ... Jim Leyland has walked this tightrope before. Verlander isn't a perfect comp — he was three years older when he broke into the rotation, and he had a better K/9 — but he was handled in much the same fashion, and he has turned out OK.
Max Scherzer, the third starter, was part of the three-way deal that moved Curtis Granderson to the Yankees. Big arm, turns 25 in July, some question his durability. He may be another one Leyland has to baby. Or he might be great.
But then come the problems — Jeremy Bonderman, Nate Robertson, Dontrelle Willis. (Armando Gallaraga, who went 13-7 in 2008, has already been shipped back to the minors.) None of the three have been useful for at least two seasons. I can't imagine that the Tigers have much confidence in any.
That Willis is even in the discussion is a surprise. His command this spring hasn't been impeccable, but it's been sufficient.