Barcelona president Joan Laporta said a "cycle has ended" at the club and warned big decisions will be made as a "renewal process" begins in the coming weeks.
Laporta, who was elected for a second spell as president in March, also slammed the way Ronald Koeman's side have chucked away the league title in recent weeks as "incomprehensible."
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Barca had their fate in their own hands five games ago, but have won just once since then and will end the season outside the top two for the first time since 2007-08.
"I always said we'd assess the team at the end of the season in terms of performances and results," Laporta told reporters on Tuesday at an event organised by Diario Sport.
"We won the Copa del Rey, which we are proud of, but we were knocked out of the Champions League early and have lost La Liga incomprehensibly from my point of view.
"A cycle has come to an end and we are working on a renewal process. From next week, you will see several decisions which must be taken. We have to work hard to build a competitive team to win league titles and Champions Leagues.
"When I speak of a cycle coming to an end or about renovation work, it's because it's what I believe must be done."
Laporta's comments will cast further doubt on Koeman's future. Sources told ESPN earlier this week that the club is already exploring possible replacements for the Dutchman.
Koeman, 58, took over last summer in difficult circumstances and did well to steady the ship after the 8-2 defeat to Bayern Munich in last season's Champions League.
However, after winning the Copa del Rey and getting Barca back into the title race, Koeman's side has regressed in recent weeks, leaving Atletico and Real Madrid to battle it out for the title this weekend.
Barca travel to Eibar on Saturday for their final game of the season with nothing to play for.
Laporta's threats are likely to extend beyond the coach, though, with sources telling ESPN Barca are keen to move on several underperforming players this summer.
Neto, Junior Firpo, Samuel Umtiti and Philippe Coutinho are some of the obvious candidates to leave the club, but some of the more established, long-serving players could also be in the firing line as Barca look to reduce their wage bill.
To tackle the changes needed, ESPN revealed on Tuesday that Barca can count on a credit line of up to €500 million from an American investment bank, with Laporta calling on €100m to settle backdated payments owed to wages.
With gross debt standing at nearly €1.2 billion, to renew the playing staff sources say Barca will also need to sell several players and cut salaries.
Eric Garcia, Memphis Depay and Sergio Aguero have all held talks with Barca about joining this summer when their respective contracts expire in June, but a source said Laporta would also like to raise the money to make a statement signing.
In the meantime, Barca must also find the cash to renew Lionel Messi's contract. His deal expires in June and he's not yet made a decision on his future, but Laporta's said he's "convinced" he will stay at Camp Nou.
Source: espn.co.uk