Head coach Mel saw his side, who sit 16th in the table, suffer a 2-0 defeat at Hull City on Saturday.
The Spaniard's mood was not improved by knocks to defender Gareth McAuley and striker Victor Anichebe.
"McAuley's got a very swollen ankle and Anichebe has a muscle issue." said Mel.
"McAuley's injured, Billy Jones too and Anichebe is possibly injured too.
"It's a problem because the next match (at home to Cardiff City) is a big, big match for us."
Mel is in no doubt as to the importance of Saturday's game against Cardiff, after all of the teams in the Premier League's bottom five lost on Saturday.
"I always want to win," he said.
"It was not possible (against Hull) but Fulham lost, (Crystal) Palace lost, Cardiff lost, Sunderland too, so the next game is a big game for us.
"We need to play well with attention and hard work. We have to continue because every week the table changes."
