Uruguay international Caceres has become the latest transfer target for Barcelona and his departure would leave the Yellow Submarines short of defensive options.
The club are yet to confirm that Portsmouth centre-half Campbell would be their preferred choice to marshal their defence next term, but they have previously expressed an interest in the England international.
Villarreal director Jose Manuel Llaneza admits that the club will look to bolster their backline over the coming weeks, but has refused to rule out the possibility of Caceres remaining at El Madrigal.
"Caceres is definitely in our plans for next season," he said.
"But if we reach an agreement with Barca then it becomes clear that the priority will be to reinforce our defence."