Detroit Lions receiver Calvin Johnson is a game-time decision ahead of the encounter with the Atlanta Falcons at Wembley on Sunday.

Johnson has been suffering with a lingering ankle injury and he has been listed as "questionable" for week eight after a third consecutive day of limited practice.

The 29-year-old received a boost with coach Jim Caldwell insisting that he "did a pretty good job" on Thursday in proving his fitness.

However, Caldwell is suffering from an injury crisis across the roster ahead of Sunday's game, with Reggie Bush and Brandon Pettigrew doubtful while Eric Ebron and Joseph Fauria have already been ruled out.

Johnson did not play in week seven and he had been used in more of a decoy role in previous games as he continues to struggle with the ankle issue.