I thought your memory was better than that. Top ups were used at the beginning of 2015 for the NAB Challenge before the AFL Tribunal Verdict when most of the 2012 players still on the list were provisionally suspended , only to be found not guilty by the AFL before ASADA appealed to CAS.
Brown, Walla and Hartley were part of the top up squad and trained as part of the AFL list until the not guilty verdict on the 31st of March clearing the provisionally suspended players to play against Sydney in the first round with no preseason games.
I found a couple of articles relating to this time to remind you, but probably digressing a bit too much for this thread. Although the second article indicated that Hartley didn’t pass the medical (which I’d forgotten) and didn’t end up playing in the NAB Challenge, but the saga certainly brought him to the club, and Dodoro’s attention, in the first instance.
So here’s a link - (and I wasn’t meaning to rub it with posting the below thread title - it’s just a happy coincidence):