Centres have rarely ever changed sides of the ruck. Either right or left is a specialised position(passing right to left and vicky verca and defending in either direction) and side preferences are automatic through personal strengths and weaknesses.
Suli is a turnstile on his FAVOURED side...imagine how bad he would be on the other.
Defending in the second row coming off an injury layoff...someone is taking the plss.
Not so .... when you have a dominant senior centre, say Lyon, and another centre comes into the team, the new guy takes whichever side Lyon doesn't want ... it has ever been thus ... and many players have played most of their careers on the side they least preferred ... same with wingers ...
You may have a preferred side ... but that is all it is ... preferred ... and your coach will try to match that to players, but at the end of the day ... you play on the side the team needs you to ..