Rapheal Guerreiro
Portugal left-back Guerreiro should also be high on Koeman’s watch-list as Leighton Baines’ performances continue to decline as he gets older.
Baines turns 33 in December and has plummeted down the England pecking order after losing a yard of pace on the left flank. Guerreiro, who can play as a left midfielder as well as a left-sided defender, is just getting started.
The former Lorient defender, 23, scored a remarkable seven goals and added 10 assists for Borussia Dortmund this season, and Koeman must do all he can to convince the French-born defender to move to the Premier League with Everton to replace Baines.