Gareth Raynor is a doubt for the trip to the capital to face Harlequins RL on Saturday (Saturday July 22nd), kick-off 3pm.
Raynor, who has made 122 appearances for Hull FC scoring 76 tries, suffered a hamstring injury during The Black and Whites victory over Warrington at the weekend.
The explosive Great Britain winger scored 18 tries in all competitions in the 2005 season, he has followed up his form with 14 tries so far in engage Super League XI.
Danny Washbrook, who left the field with a dead leg following a collision with Warrington's Mike Wainwright is expected to recovery, while Paul Cooke (kidney stones) has been given the all clear after visiting hospital on Saturday evening.
Peter Sharp explained: "Gareth Raynor is doubtful for Saturday, we will wait and see if it's a grade one or two hamstring injury, but at this point he is a doubt for the trip. We will see how Danny (Washbrook) and Paul (Cooke) go in training this week and take it from there."
The severity of injury to the hamstring muscle is classified according to the following grades:
Grade 1 is a mild strain with few muscle fibers being torn.
Grade 2 is a moderate strain with a definite loss in strength.
Grade 3 is a complete tear of the hamstrings.