Hearn remains in talks with Deontay Wilder's camp regarding a showdown at some point in 2018, but Joshua must also fulfil his WBA mandatory obligations, with Povetkin due a fight for that respective belt in the near future.
With negotiations ongoing with Wilder, Hearn has indicated that a September bout with Povetkin will probably represent Joshua's next outing in the ring.
Hearn is quoted by Boxing News Online as saying: "The Povetkin deal is virtually done. The Wilder one is not, but we're talking every day. It's just a case of whether we get that done.
"Joshua would like to fight in September; the Wilder fight doesn't really work in September, mainly because of the Canelo [Alvarez] fight; the PPV doesn't really work out. If he fights Wilder it'll be October, November in the UK, and if he fights Povetkin it'll be in September.
"It'll either be Povetkin then Wilder, or Wilder then Povetkin, but if it's Povetkin next, the Wilder fight will definitely be signed before we go into that fight."
A date of either September 22 or September 29 at Wembley Stadium is a possibility for Joshua's clash with Povetkin.