His agility running score during the combine was in the elite category, he was also very quick, nothing like Ziebell at all.
Ziebell was a really good mark for his height, which is why he was effective up forward, really good at reading the ball in flight early, that also translate well in a defensive role. I don't know if Bonar had those traits to the same extent. He might work out as a defender, but we didn't target him for a defensive role and he will be in a vulnerable position if the likes of Perez and Goater reach their potential.
I don't mind the club moving players to different roles after they have been developed for their main role and realising they aren't going to make it, ie Ziebell was played as a midfielder and then a forward for many years, Noble though he could get the most out of Jack's remaining years as that distributor of the ball down back. When players like Tarrant and Hansen were moved back, they spent a fair bit of time developed as forwards. I don't think Bonar got much of a go in the middle and didn't spend much time in development for that role.
I hope it works out for him but he is going to have to contend with a new breed of defenders with elite kicking skills.