Fortunately, Yahoo has put the 'Minimum Innings Pitched' (to date) link on H2H Team pages.
Unfortunately, in custom leagues, the info is wrong (at least in my leagues).
Each of my H2H leagues with min innings set to something other than the default (7), Yahoo tells me I've already met the minimum when I haven't. For example, one league has a 27 innning minimum and Yahoo tells me I've met it even though I've only played 3.1 innings.
Blessed are the cheesemakers.