Lallana, 29, has made just 10 appearances in all competitions this campaign due to a thigh complaint.
The England international last started for Liverpool in the 2-1 FA Cup win over Everton at the beginning of the year.
Speaking ahead of his side’s Champions League second leg against Porto in a last-16 tie they lead 5-0, Klopp said Lallana still had a big part to play in his team.
“Adam, absolutely, was an integral part of the team and with the competition we have for Adam it is still usually not a problem for him, because he is important to us,” he said.
“But he needed only time. Life is to learn from your mistakes and we all have to learn.
“We made this mistake – he looked fit. Maybe two little setbacks, not the biggest setbacks, but in and out, in and out, and that makes no sense so now we have to build with him. He is coming close.
“But of course he now has no rhythm, which is another thing. We still need him, we will use him still.”
Even without Lallana, Liverpool sit third in the Premier League and are on track to reach the last eight in the Champions League.
Klopp is unsure if the midfielder will face Porto, but said Lallana would eventually get his chance.
“He is cool, he sees the quality of the team is good, but he is always one of the guys who pushes the level in training onto the next level, because he is always so intense in all the things he is doing,” he said.
“So the time will come for him 100 per cent. Whether it is tomorrow [Tuesday], I don’t know.”
