Rodgers has cited the example of Dortmund as a club who won the European Cup before falling on financial difficulties and a decline.
“You can challenge [for the top four] without spending £80m in one summer,” Rodgers said. “Look at the example of Borussia Dortmund. A team that won the Champions League and then struggled financially.
“They went out and rebuilt and it took them four to five years to push on. Then they won the league and their European work suffered. This year you can see they have put their focus on Europe and they have lost their title. That’s a team that has been growing over five years.”