There are three ways things can go when a player is made to stay.
1. They get on with it, play as well as they can. This usually comes with some kind of promise; Silverware, future signings, sold at a future date.
2. Disastrously, player virtually gives up, plays badly, fakes injuries etc
3. Lacklustre performances. Whilst not playing badly they don't give it all they've got. Most of the time the player is playing for time ie their contract is running down or knowledge that the buying club will be back and the selling club will be tempted by the money.
From what I've seen its more of a 3. Hardly seems to be Soton's stand out defender