The Boston Celtics seemed to do a quick 180 on top prospect Markelle Fultz, and now we have may have a bit of an idea why.

According to what ESPN’s Michael Eaves tweeted on Sunday, some members of the Celtics organization were not impressed by Fultz’s workout and pointed to a perceived lack of explosiveness on the part of the former Washington star.

Fultz seemed signed, sealed, and delivered to Boston at No. 1 overall for months. Initially, he scheduled a workout with only the Celtics. But Boston abruptly agreed to a blockbuster deal with the Philadelphia 76ers on Saturday, swapping the top pick for the No. 3 selection and an additional first-rounder.