Liverpool manager Jurgen Klopp believes striker Daniel Sturridge has to learn more about the difference between "serious pain and what is only pain" in order to conquer his injury problems.
The 26-year-old pulled out of the squad for the 2-1 Europa League win over Bordeaux on Thursday after reporting discomfort in his foot.
Sturridge has missed almost as many matches as he has featured in since joining the club in January 2013 and hip surgery in May has restricted him to 252 minutes over three appearances this season.
He featured in only 18 matches in the previous campaign because of thigh, calf and hip problems and Klopp has yet to play him since taking over as manager in mid-October.
The German has made allowances for the amount of time Sturridge has been sidelined but admits the striker cannot be given an extended period to recover because they are deep into the season and competing on three fronts.
"The situation is Daniel was very often injured in the last few months, and maybe years, so it is normal when you get back in training usually it is not the quality, but you need training," he said.
"Your body has to learn to adapt to new intensities of training and in this time you have to learn what is serious pain and what is only pain.
"Everyone wants him back on the pitch but we all have to learn.
"Now we can say (his latest issue) is not that serious but it is not possible to go on as before so we have to react to every situation - which is normal for injuries.
"When Daniel comes back usually after this long break you would train five weeks in a row and play only in friendly games.
"That would be the best, but of course we know the world is not perfect so we have to try the best and the quickest.
"It is a really long period so now we have to stay patient I am sorry to say: sorry for you, sorry for me, sorry for him."
Klopp could not say whether Sturridge would be fit to be included in Sunday's squad to face Swansea.
However, he revealed captain Jordan Henderson, who has not played since the second match of the season after heel problems and then a broken bone in his foot, will not be considered until fully fit.
The midfielder returned to training with the full squad this week and his manager admits he is taking it day-by-day with the 25-year-old.
"He wants (to play) but we have to wait," said Klopp.
"I am waiting for him, that is what I told him. For a player like him he is always (knocking) on the door saying 'Give me five minutes, 10 minutes'.
"I like this, but it is not always the best thing to do. He has a big step ahead of him now.
"Everything we do is 120 per cent so you need to be prepared for this. Players like Hendo have to be fit, not only 50 per cent.
"If he is in this shape we can use him and he can help us."
Klopp also questioned whether Christian Benteke, whose brilliantly-taken goal won the game against Bordeaux, is ready to start again after 90 minutes against the French club.
"I don't know in this moment if Christian is capable of playing two games in three days. We will have to decide," he said.
"But it is not the most difficult situation at this moment with the strikers because we have Christian, Divock (Origi) and Roberto (Firmino) who are good.
"We need all of them for this big number of games."