For the past couple of years, we've had the following rule:
Any starter not having a relief rating or having a relief rating of 0 shall, if so requested by the player's owner prior to the start of the season, have his relief rating adjusted to "1."
That's fine, except that it doesn't conform to reality. Very rarely in MLB will a SP come into a game and pitch 1 inning. More common is a pitcher coming in to throw 3+ innings of bullpen-saving relief.
I propose that the rule be modified to let an owner request that a SP without a relief rating be given a relief rating of 1, 2, or 3. Thus, if you want your SP available for longer relief you can rate them as such, but if you're worried about innings or something you can still have a lower rating.