Everton received a heavy blow on Tuesday as manager Roberto Martinez announced that goalkeeper Tim Howard will be out for up to six weeks with a calf injury.

The 35-year-old sustained the injury in the first half of Everton's 1-0 loss at home to Stoke City last Friday and was replaced by Joel Robles, who deputised for him again in Sunday's 3-2 defeat at Newcastle United.

"Tim Howard will be out between five and six weeks with a calf injury," Martinez told a press conference ahead of Everton's New Year's Day game at Hull City.

"I thought Joel was very calm against Stoke and did well against Newcastle. But we will assess whether we need cover."

The loss of Howard, who starred for the United States at the World Cup, falls at an inconvenient moment for Martinez, whose side have slipped to 12th place in the table after winning only two of their last 10 games.

A six-week lay-off would see Howard miss league games against Hull, Manchester City, West Bromwich Albion, Crystal Palace and derby rivals Liverpool, as well as next week's FA Cup third-round tie with West Ham United.