"He's been to see the specialist and for now we think that he's going to have a special injection and hopefully that will be it," the Swede told the club's website, mcfc.co.uk.
"We are not talking about operating at this moment, so I hope he can start training on Monday, but we are not sure yet.
"He has pain and has done for a long time and of course after training and after matches it's got worse and worse."
Former England coach Eriksson was grateful to receive the support and co-operation of under-21 boss Stuart Pearce in regards to Johnson's injury.
"I appreciate very much Stuart Pearce. I spoke to him yesterday and they agreed that he will not play for the under-21s," added Eriksson.
"That's very good for Michael and it's good for the under-21s as well because that means almost for sure that he'll be ready for the games in November."