Over the last 4-6 weeks TBell has been playing 84 to 86% time on ground. I will agree he was bad in the last quarter against Brisbane, as were the other mids.
One way to reduce his loading and mix things up, would be to send him to the goal square and bring Joe into the ruck for a bit more of the 85%, lets say we drop his ruck time to 80%. OK, he is not a highly mobile forward, but he is a good contested / pack mark and Joey can play really well on the ball.
The other way would be to cut back on his training loads just a little and do whatever they can to improve his recovery, so he is as fresh as possible at the end of games.