According to the Mirror, Lallana took the news well and still respects Southgate, despite his understandle devastation upon receiving the call.
Lallana has started just three games for Liverpool this season, due to a string of injuries that he has struggled to shake off.
A trip to South Africa for specialist treatment wasn't enough to convince Gareth Southgate that he deserves a seat on the plane - and the England manager has told Lallana on the phone that fitness was the only reason he wasn't included.
In fact, Southgate made several calls to Lallana to monitor his progress, before breaking the crushing news that he would not be travelling to Russia.
Lallana has, though, been named on the World Cup standby list with James Tarkowski, Tom Heaton, Lewis Cook and Jake Livermore.
This means that he will be with the group for pre-tournament warm-up games against Nigeria and Costa Rica, alongside the other four players on standby. He could still feature in the World Cup if England suffer an injury, although that depends on whether his involvement in the Champions League final and the warm-up games can improve his fitness enough.
Speaking about his brave decision to exclude Lallana, Southgate told the Mirror: “History tells us that one of those standby players may end up in the squad, as it’s very unusual for us to get through the end of the season and our two preparation games without any issues.
“All of the guys on standby have been really professional in their approach to this. They recognise there’s still an opportunity and we've had a lot of conversations over a period of time with them about their situation.”