Maybe because as a reliever Puk has a 2.08 ERA, a 0.748 WHIP and a 5.5 K/BB this year in over 30 IP, a solid track record over multiple seasons, and 2.3 years of team control. His four starts, where he got shelled in a role he clearly wasn't cut out for, heavily impact his season stats (ERA almost 10), and lead to wildly erroneous evaluations.
It doesn't matter anyway, because Falvine were asleep at the wheel and he's now gone. Cheaply.