I believe during the final couple years of his playing days
he was around 260 lbs or so. I would consider that to be in the light end of the DT weight scale. If Jank has a quick first step, then he probably could play DT at that weight.
Now if we are talking about players, who might meet the DT criteria, then former Kentucky QB Jared Lorenzen might be a better candidate than Jank. While at Kentucky, he weighed between 270-290 lbs and at 6'4" would have good height for a DT. I did hear after that after college and his multiple attempts to have a pro career (both indoor and outdoor) that his weight eventually got to be over 500 lbs. The last I heard anything about him, which was around April 2018, it sounded like he had lost over 100 lbs and may be on the right road to getting his weight under control.