Glasner feels 'abandoned' by Palace hierarchy
Glasner, who revealed on Friday he will leave the club when his contract expires at the end of the season, had to cope without captain Marc Guehi with the centre-back set to join Manchester City.
Palace also cashed in to sell Eberechi Eze to Arsenal in August and could reportedly lose star striker Jean-Philippe Mateta to Juventus before the end of the January transfer window.
Glasner led Palace to their first major trophy by winning the FA Cup last season.
However, their defence of the competition ended in embarrassing circumstances with defeat to sixth-tier Macclesfield last weekend.
Glasner's side have looked exhausted in recent weeks after already playing 34 times this season in four competitions.
The Austrian defended his players for their poor run as he put the blame on his superiors for not arming him with a stronger squad.
"I feel we are being abandoned completely," he told the BBC after the Sunderland defeat.
"I can't blame any player. They did everything they could and this has been going on for weeks and months now.
"We have 12 or 13 players from the squad available and we feel no support.
"The worst thing is selling our captain one day before playing a Premier League game.
"We are preparing, it's the first (full) week we are training since September, and then we are selling our captain one day before a game. So I have no understanding of this."
Glasner, 51, has been linked with taking over at Manchester United and Tottenham next season.