Former striker Dimitar Berbatov believes Casemiro's importance at Manchester United could put West Ham United midfielder Declan Rice off sealing a move to Old Trafford amid ongoing speculation about his future.
United, who are currently third in the Premier League table, five points shy of the summit, are understood to be already planning to recruit a younger central-midfielder ahead of next season.
United strengthened their midfield options with the additions of Christian Eriksen and Casemiro last summer and drafted Marcel Sabitzer in on loan last month as emergency cover.
The Reds, though, are planning to bring in a younger and more dynamic midfielder in the summer and still hold an interest in Frenkie de Jong of Barcelona and Borussia Dortmund sensation Jude Bellingham.