Gylfi Sigurdsson, Everton, £45m
Everton are hovering above the relegation zone and need more from their record signing. He hasn't registered a Premier League goal or assist yet this season, but scored the goal that clinched World Cup qualification for Iceland. The Toffees will be hoping their new arrival will have taken confidence from such a memorable international break.
Alex Oxlade-Chamberlain, Liverpool, £40m
He is yet to start a league game for Liverpool but he did himself few favours as the Reds crashed out of the EFL Cup at Leicester. Sadio Mane's injury may give the former Arsenal man a route into Klopp's side and a good performance against Manchester United would be the perfect way to kickstart his Anfield career.
Michael Keane, Everton, £25m
The centre-back has looked shaky at the back for Everton, who conceded 12 goals in four games. A collective dip in form which has highlighted the defender's lack of confidence. If Everton are to climb their way up the table, Keane must step up his performances against the better sides.
Nathan Aké, Bournemouth, £20m
His form has dropped since he signed a permanent deal to become the Cherries' all-time most expensive signing. Bournemout boss Eddie Howe put a lot of faith in the 22-year-old former Chelsea man after a successful loan spell last season, but he has been far from convincing.
Andre Gray, Watford, £18.5m
He scored nine league goals for Burnley last season and Watford splashed out £18.5 million on the 26-year-old. It took him 510 minutes to score his first league goal for the Hornets, where he has struggled to make a real impact.