I'm as happy as the next guy to laugh at striker's hyperbole, but I do think there's a significant risk to not acquiring a starter, even if that guy isn't an "impact arm." No, Flaherty, Montgomery, Rodriguez, Lorenzen and the like aren't really impact arms, but they do add depth to the rotation and give you Fried insurance. They reduce the chances you have to do a bullpen game or something similarly desperate in the playoffs. And while the division is in hand, one more competent arm in the rotation means one fewer start for the Shuster-Dodd-Soroka-AJSS quartet for the rest of the regular season, which could be helpful in maintaining the best record in the league.
I'm not going to lose too many nights of sleep over this, and considering the state of the farm system it's probably necessary to take a break from raiding it for a season or two. But inaction has its risks as well.