Crystal Palace boss Oliver Glasner has launched an attack on the Eagles' board over their handling of the departure of another key player after a deal to sell captain Marc Guehi to Manchester City was completed on the eve of their 2-1 defeat by Sunderland. Glasner's comments came in a fiery rant following the defeat that saw his side slip into 13th. The south London club are in turmoil with significant departures confirmed after boss Glasner announced on Friday that he will leave the club at the end of the season when his contract expires, a decision made in October to seek a "new challenge". Compounding the managerial news, the club has agreed to sell team captain Marc Guehi to Manchester City for an initial $26.7 million (€23m). This has caused significant friction, with Glasner publicly criticising the board for selling a key player one day before a game.Further player movement is anticipated, as striker Jean-Philippe Mateta is also open to a new challenge, with Juventus holding talks with his representatives for a potential transfer. Having already sold Eberechi Eze to Arsenal last summer, the club faces a challenging period of transition and a potential exodus of its best talent, leaving a significant rebuilding job for the next manager. And Glasner has revealed the levels of frustration with the club are at a boiling point. After the match, Glasner told the BBC: "I feel we are being abandoned completely. 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, 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. I have always kept my mouth (shut), but I can't because I have to defend these players, because it was the 35th game today. Yes, we get under pressure here and we are unlucky. But again, you can't react, we can't help them, it makes it really tough." The Palace boss continued: "If you get your heart torn out twice this season, one day before a game, it was with Eze in the summer, it was with Guehi now. What should I tell the players all the time? What should I tell them? And then I see the performance today for 50, 60 minutes - it was not easy with all the circumstances going here with 12 players from the squad. I look at the bench, I can't react, just kids on the bench, and this has not happened yesterday, this is weeks ago. That's why I'm really frustrated today." When asked if he wanted to leave sooner than the end of the season, he added: "No, never, I would never. I will go with this group of players until the end. I have so much respect for their character. I see they're disappointed and I know how hard they are working, I see how hard they are fighting at the end. Never, no chance. I have said to the players we have to stick together, if we don't get the support it's us that have to do it. There is nobody else, we are the only ones, we are the ones who have to play."Add GOAL.com as a preferred source on Google to see more of our reportingGlasner will be left to make plans without his captain and, potentially, also lose talismanic striker Mateta in the coming weeks. And there’s the small matter of the London derby with Chelsea looming on the horizon, with no guarantee Glasner will be in the dugout at Stamford Bridge for the clash.