The Liverpool forward suffered a groin injury and will be ruled out of England’s games against Spain and Switzerland.
The England international was part of the 22-man squad training session at St George’s park on Tuesday but was pulled up and left early to be assessed.
England have confirmed that the 30-year-old who has struggled with injuries will go back to his club for treatment and will not participate in the first UEFA National League matches.
Lallana featured only 17 times for the past one year due to injuries.
England boss southgate said that the squad have been reduce to 22 men after raheem sterling have been withdrew on Monday evening with a back problem.
Lallana only played once this season in the win at Crystal palace.
The rest of the players trained together for the first time since their departure from the world cup third place when Anfield striker Dominic Solanke was called from the Under-21s to bolster numbers.