Forwards are going to struggle when the team struggles but that aside they are pretty silly stats anyway. All 3 of those players went off injured in games and Hawkins and Rohan only played 3 in that period including the ones they went off injured in so tiny sample size.
Yeah, weird picking Rohan and Hawkins as "dropping off" as both were injured in that Round 19-24 phase. Not to say that they didn't drop off statistically... but because of injury. Close is more justified, though he was a bit of a barometer - his better games were in our wins. Considering some of the insipid team-wide games late in the season (Freo, Brisbane, St K) I'm not surprised to see him drop off.