Manchester United manager, Jose Mourinho, expects a difficult test against Arsenal in the Premier League on Wednesday.
Arsenal's Europa League match against Vorskla Poltava on Thursday is in doubt after the Ukrainian side said they could not guarantee they would be able to fulfil the fixture.
Welbeck, often used as a backup striker by Manager Unai Emery, underwent two operations after suffering a broken ankle against Sporting Lisbon in the Europa League earlier this month.
Salah was seen training with a protective cast on his forearm this week, but Klopp dismissed any fresh injury concern relating to the Egyptian.
Juergen Klopp’s side, second in the league standings on goal difference behind Manchester City, have only dropped points against the champions and Chelsea in their opening 10 matches as they bid for a first top-flight title since 1990.
The run is their best for 11 years, and it is also the first time that the English giants have beaten a Portuguese side away from home