Latrell Mitchell struggled at fullback and was eventually moved to centre where, without the burden of fullback positional play (especially in defence), he is now one of the best in the game. This should be an option for TT.
As much as Mitchell is a talented player, one of the main reasons he is seen as one of today's better centres is because of this obsession everyone seems to have nowadays with how great players are with the ball in their hands.
For mine, a great centre is one who can not only attack.....but can defend as well. Mitchell can attack the live long day, but his defence, even in the centres where he is not the last line, is piss weak most times.
A great centre is a Bob Fulton, Michael O'Connor, Terry Hill, Steve Matai, Jamie Lyon, or if you want to go outside of Manly someone like a Mal Meninga or Andrew Ettingshausen. All were brilliant with either speed, the ball in hand or both. But all probably stopped more tries being scored with their defence than they ever scored or created themselves. Players like Latrell Mitchell and James Roberts may be great attacking players, but for mine their defence is highly questionable. And until (if) they become strong defenders, to me they will never be greats of the game no matter how many tries they score or rep games they play.
As for Tommy.....playing him in the centres or on the wing for NSW and Australia would be OK because those sides are generally stacked with top players who can do similar or same that he can. But for Manly I think playing him in the centres limits his involvement because he'd be stuck on one side of the field. At fullback he can join (or run through) the line at any point.
Sure he has a few errors in his game that he needs to work on. But I wouldn't be moving him from fullback.....not for Manly at least.