mihoba is correct, of course, but I think it is a good point to say there are some good options if one or more fails, and even more options, possibly, as the season progresses. With the solid defense, the pitching might have a little leeway, being able to pitch their game and trust to the fielders.
Backe is a concern for #3, but he can eat some innings and come up big.
Clemens could still come back and take up some slack in a month or so.
Yeah, Roy and Andy need to stay healthy.
I don't expect much from Wandy, who seems to be the pitcher with the least potential out of this group. Taylor has done nothing in the bigs so far, but he looks to have a higher upside if he can stick for a while.
Offense and defense are both better to start the season. It is a good place to begin.
I'm still not sure about Munson.