Liverpool manager Jurgen Klopp says it is “clear we have to do something in the summer” amid his side’s struggles this season.
The Reds were beaten 5-2 by Real Madrid on Tuesday in the first leg of their last 16 Champions League tie.
Liverpool are also eighth in the Premier League – albeit with games in hand on some of their rivals – during an inconsistent campaign.
“We know we have to improve and change things and we will,” said Klopp.
“We cannot do it now but it’s already clear that we have to do something in the summer. For now, we just have to go through this and fight back.”
Liverpool midfielders James Milner, Naby Keita and Alex Oxlade-Chamberlain will be out of contract in the summer along with forward Roberto Firmino.
A number of players have also been struggling for form this season, with Klopp’s side seven points off a top-four spot in the Premier League heading into a game at Crystal Palace (19:45 GMT) on Saturday.
‘A few people are speeding up a little bit and you can’t ignore that’
Liverpool have played in the Champions League for the past five seasons, during which time they won it in 2018-19, while losing to Real Madrid in the 2017-18 and 2021-22 finals.
“It’s not helpful [if we don’t get in the Champions League],” said Klopp.
“We have to start doing work earlier before we know where we will end up position wise and European competition wise. These things are clear.
“We played five years in a row in the Champions League and went through to the final three times, which is massive from a money point of view.
“We built a stand and training ground – the club is in a really good place – but around us a few people are speeding up a little bit and you can’t ignore that. You cannot ignore these kinds of things.
“It’s still about finding in the right players. It’s not about bringing a lot, it’s about right [players].”
Injuries have also had an impact for the Reds during the current campaign but their exploits are in stark contrast to last season when they played every game possible, making 63 outings in pursuit of the quadruple.
They won the FA Cup and League Cup – competitions they exited at the fourth-round stage this season – but missed out on winning the Champions League and Premier League.
And, while Klopp said “this team has a wonderful history”, he added “one of the main reasons” he signed new contract until 2026 was because he knew there would be a period of transition.
“The way that this club is led is by not splashing the money. Our transfers always have to be on point. That makes it really tricky,” he said.
“We cannot make four transfers before we know who will leave the club and these kind of things.
“Last year was not a season for a big change. We played until the last moment and, if you want to change at this club, we cannot just bring in players and realise later that no-one wants to leave. It doesn’t work like that.
“It’s not possible to start it early because we have final after final, played the season until the last minute, played the Champions League final, then we had a short break, then a lot of injuries and then the World Cup.”
Klopp’s comments follow Liverpool owner John Henry stating he is not selling the Merseyside club.
“We have to make our own plans and that’s what we do but based on the way this club is led,” said Klopp.
“It’s obviously different to other clubs, that’s how it is. It worked out so far and we have to see if it will work still or if we have to adapt.
“That’s something for us in the offices when we are not on the training pitch and for my conversations with the owners and all these kinds of things.”
