The 30-year-old's future at The Hawthorns remains in doubt, with the Baggies' relegation to the Championship activating a clause in his contract which allows him to leave for just £3m.
Evans is widely expected to secure a move to another Premier League team this summer, and the Express & Star reports that he rejected the chance to make one final farewell appearance.
Both Evans and Claudio Yacob - who also missed the 2-0 defeat to Crystal Palace - trained throughout the week, but Evans allegedly sent a text before a training session on Saturday to inform the club that he was unavailable for the weekend.
Caretaker Baggies boss Darren Moore insisted after the match that both players had permission to miss the game and that neither will face any further punishment.
Evans failed to make a single start under Moore as West Brom gave themselves hope of survival with a late-season revival.