Scharner, a veteran of five Premier League seasons with Wigan, said that avoiding relegation is as much mental as it is physical.
On West Brom's last season in the Premier League, he said: "Maybe the belief was missing.
"Most of the small teams, they don't believe that they can get something out of the big stages.
Scharner added that he hoped to bring more mental strength to the club.
"To stay in the division it's one of the biggest points," he said. "It's time to roll up our sleeves and fight to stay in the league."