Vaesen told Walfoot: "[Alisson's arrival] doesn't change the situation . Our goal is to find a solution for Simon to play and Alisson's arrival doesn't change that.
"We know that a player of €60m-70m (£53.5m-£62.5m) won't find himself on the bench. We are looking at the situation and looking for a solution to his playing time. There are options, the next few days will be decisive."
Mignolet has made 200 appearances for Liverpool since a 2013 move from Sunderland.