Rossi is wanted by Barcelona and Tottenham.
"If we get an offer that is good for Villarreal then it will be accepted and we will thank the player for all his efforts. From there, we will hire players who make Villarreal even bigger," Garrido told AS.com.
"There are many rumours which suggest otherwise, but all players reach a certain stage, and we have to address their needs.
"If he does leave then we will replace him with the necessary players. Rossi has played many games and scored many goals and so we have to prepare for possible sales."