Duran's been iffy at best in non-save situations. If you felt the need to use a high-leverage arm in the 7th, when you have Sands, Alcala, and Jax available, why do you go for the pitcher that's least comfortable in that situation?
With the lack of days off the rest of the month, Duran's going to have plenty of opportunities to pitch. There was nothing that said Rocco HAD to use him today.
It was a bad decision.