Sure, there are different ways to approach the goal but right now, Odorizzi can pitch 150+ innings of well above average ball. Could he maybe pitch six if an opener is used? Sure, but then you're tasked with finding an opener that can pitch, say, 80-100 innings a year of above average ball because at the end of the year, roughly the same number of innings need to be pitched by one baseball team. Where the innings come don't really matter in the grand scheme of things. The point is avoid opposition runs for nine innings a game. There's also the problem of a hard cap of 13 pitchers, which eliminates the option of teams using bullpen games constantly. Thirteen pitchers just can't pitch that many innings unless you go out and find a bunch of 100 inning relievers, which is a different challenge in itself, one that may be impossible given payroll constraints and actual league talent available.