Liverpool fullback Trent Alexander-Arnold is facing a spell out due to injury.
Alexander-Arnold picked up a knee strain in Sunday's FA Cup win at Arsenal.
"Trent hyperextended his knee, so he has a little tear in the lateral ligament of his knee," said Lijnders.
"He had a scan. He will be out for probably three weeks. It's a big blow. We will really miss him."
Lijnders added: "We will have to find new dynamics without him because he made our game flexible. Even in bad spells, he was the one putting the balls where we needed the difference.
"He will get some rest and then hopefully he can come back to where he was. Because this guy was decisive in all the games and was the one who created constantly for us from deep."
