Everton defender Phil Jagielka says the club cannot advance because they "haven't got any money".
David Moyes' side are 10th in the league but are closer on points to the relegation zone than the top six.
"You see other teams doing so well who finished below us before, so you can see the fans' frustration," Jagielka, 29, told Football Focus.
"We can't buy expensive players to take the squad to that next level. All we can do is work with what we have."
This season has seen a fans' group
"It's hard for the fans," England international Jagielka added. "We've done so well to finish sixth, seventh and eighth in the last few years.
"You may think if someone came along and put some investment in that we could maybe kick on. We haven't got any money.
"All we can do is try to be as good a team as we have been in previous years and stick together when the going gets tough.
"We roll our sleeves up and, normally, after Christmas, climb the table."
Despite the financial constraints, Jagielka, who has won 10 England caps, is hoping for some fresh faces when the transfer window opens next month.
"Unfortunately we had to sell to balance the books but hopefully we can bring in a couple in January," he said.
"There are probably 15 players that are in the squad every week and five or six young lads who can come in and boost the team."
Amid the protests from fans, chief executive Robert Elstone revealed "genuine conversations" had taken place about a potential takeover from interested parties.
But from the dozen initial approaches received, none has produced a sale. Some experts believe Goodison Park is part of the problem, with would-be buyers unwilling to invest in building a new stadium.
Jagielka, who signed for Everton from Sheffield United for £4m in July 2007, said: "The issue of the ownership of the club has been going on for about six years.
"Are we getting new investors or aren't we? The lads don't see anything of the protests, but we read about it in the paper every day."