The England international has missed the last two games after a setback in his return from a long-term thigh injury sustained during pre-season ahead of the season, making this a season to forget for Lallana, where he has been frustrated on the sidelines.
The German said: “It's really unlucky. It was a really serious injury in the summer. Because of Adam's quality and attitude in training, it looks immediately like we can put him in, [but] physical-wise he's not fit.
“The two things that happened after his big injury were in the 10 or 15 minutes after he came on. From nil to 100 in a second, and that's maybe what caused the problem.
“We really tried to be sensible with it, to do the right thing. But it didn't work, twice. It's really not a big thing, three games is like not being injured.
“He's maybe available for Tottenham, and if not then he'll have missed three games. That's really OK but of course it's not cool. The body needs to adapt again to the intensity.”