Thiago Silva has warned things could get worse before they get better for Chelsea unless the club "stop and put a strategy in place".
Chelsea lost 2-0 to Real Madrid at Stamford Bridge on Tuesday to exit the Champions League 4-0 on aggregate at the quarter-final stage.
The Blues also fell short in both domestic cup competitions and are 11th in the Premier League, despite spending more than £600million on new players over the past year.
That has coincided with the Todd Boehly-led consortium taking over from Roman Abramovich, with the new backers having nothing to show for their investment so far.
The owners have already sacked Thomas Tuchel and Graham Potter, with Frank Lampard brought back as caretaker manager, but Silva hopes lessons will be learned.
"I think the first step has been made, an incorrect step, but it has been made," he told TNT Sports following Chelsea's European exit.
"We can't be blaming the managers if we don't take responsibility. It's a hard period for the club, with a lot of indecision.
"Change of ownership, new players arriving – we had to increase the size of the changing room because it didn't fit the size of the squad.
"A positive point is that there are amazing players in the squad, but on the other hand, there are always players that are going to be unhappy."
Chelsea have made 17 signings over the past two transfer windows – both loan and permanent arrivals – leaving a number of players struggling for any meaningful action.
"There is always going to be someone upset because not everyone can play," Silva said. "The manager can only pick 11 from a squad of 30-something – that's tough.
"Some can't make the squad. We signed eight in January, so we need to stop and put a strategy in place, otherwise next season we could make the same mistakes."
Chelsea are winless in seven matches, losing five of those, including all four since Lampard was brought in as Potter's temporary successor.
Veteran centre-back Silva, who is nearing the end of his third season with Chelsea, accepts it is down to him and his team-mates to step up.
"Everybody talks too much about replacing managers. I think we, as players, must also take responsibility," he said.
"We have had three managers this season, plus a fourth with Bruno [Saltor] where we failed to win. We have lost today, and with Lampard, we have failed to win.
"Everybody is talking about the manager, but we must look at what has been done wrong and try to change."
Chelsea have seven Premier League games remaining, starting with the visit of London rivals Brentford next Wednesday.