Sky Bet are offering 8/1 for Wigan to win the FA Cup and be relegated after they were handed a favourable semi-final draw.
The Latics will be favourites to book a place in the final regardless of who of Millwall or Blackburn they face, but they are also odds-on to be a second-tier side themselves next season, at 4/6 for relegation.
Manchester City are the 11/8 favourites to lift the trophy as Manchester United (11/4) and Chelsea (7/2) face a replay at Stamford Bridge, having drawn 2-2 at Old Trafford.
Sky Bet Football Trader Chris Spicer said: "Wigan's chances were looking slim heading into the weekend and we had them at 28/1 to lift the trophy, but a shock win at Everton and a favourable draw has seen their price cut significantly.
"However, Roberto Martinez's men also face another battle against relegation, having dropped into the bottom three following Aston Villa's victory, and we make them less likely to win the FA Cup and stay up at 12/1."