Yes, but if a starter with 70 stamina can last over an inning, with baserunners, I don't think it will be hard to have a 30 stamina rated Wade Davis last 3 batters. We've seen n the past that pitchers with 0 stamina are still effective online.
Maybe you'll need more than 3 relievers. If you intentionally make a bad rotation to save your better picks for relievers I think you could easily end up with 5 or so relief pitchers that are silver or better. I'd take that over the 1/5 chance of getting my ace gold starter. Or having to waste picks of good starters that may never see action in a game. If I spend my picks on good relievers I can guarantee them a pitching every game due to how stamina resets.