While Schneiderlin's future remains unclear, Fonte hopes that the midfielder will remain at St Mary's Stadium.
"We all know how important he is," Fonte is quoted as saying by Sky Sports News. "He's always been a very good professional. He's always been on top of his game and he does what he has to do.
"It would be massive [if he stayed]. He's one of the most important players for us, so we're just pleased that he's still with us."
Southampton play their first home game of the season on Saturday when they host West Bromwich Albion.