Hard to pin all this on bullpen management. Step back and right now our 8-man bullpen has 2 reliable pitchers in it - Neris and Alvarez. Alvarez is used a lot and is mostly a 1-inning pitcher. Now he only threw 5 pitches yesterday so maybe you get 4 or 5 outs from him, but there is really no guarantee of that and he might be needed today.
The new guys (Morin, Hughes, Parker) are probably the best we have after our top 2. One needs more than 2 pitchers so Kapler needs to use them. It is not his fault that Morin is one of his high leverage guys. That was actually the proper choice even if Morin is more suited to be the 6th or 7th man in a bullpen. It is what we have.