The shot-stopper sustained the injury in the FA fifth-round replay against Oldham Athletic, with Aston Villa's Brad Guzan set to step in
The injury, which Howard sustained in the FA Cup fifth-round replay against Oldham Athletic 10 days ago, is unlikely to end the 34-year-old shot-stopper's Premier League season, but U.S. national team backup Brad Guzan will likely take the field for crucial games in Denver and Mexico City.
“Tim is out against Wigan," said Everton boss David Moyes. "He has broken two bones in his back. We don't think he will be out for the season.
A similar injury to Newcastle United defender Fabricio Coloccini kept the Argentine out for nearly two months.
"I read that Coloccini could be out for seven weeks but we are not sure how long Tim will be out for because, obviously with a goalkeeper, he has to dive around and hit the ground," explained Moyes. "He has two fractures, but they are not bones that are supporting anything. It is off the spine. They are not weight-bearing.
"It just needs a bit of healing time. It is not like a pure fracture where you need to wait to look at it. It is a question of whether he can cope with the pain. The bones will heal themselves but it's not good."