Jermain Defoe is expected to become a Sunderland player on Friday after the final details of his transfer were tied up.
However, the Black Cats are waiting for Jozy Altidore's proposed swap-move to Toronto to be processed before making an announcement.
Press Association Sport understands the Defoe end of the deal is in place, but Altidore only flew to Canada on Thursday to push through his return to the MLS with Toronto five hours behind England.
Sources on Wearside were not envisaging any late hitches, and remain hopeful that 32-year-old Defoe could make his debut against former club Tottenham at White Hart Lane on Saturday.
It is understood that the transfer will be a straight swap between the England international and his United States counterpart with both men having been wooed with hugely attractive salary packages.
Defoe would return to the Barclays Premier League after just 11 months in Canada despite signing a four-year deal, while Altidore is just 18 months into a similar length contract, but has struggled to hit the heights since his £6.5million arrival at the Stadium of Light from Dutch club AZ Alkmaar during the summer of 2013.
Sunderland head coach Gus Poyet will hope Defoe can bring much-needed goals to his team after maintaining his impressive scoring record at Toronto, but current caretaker Newcastle boss John Carver admitted his surprise that the frontman had not settled at the club he managed earlier in his career.
Carver said: "I can't believe he hasn't settled in Toronto because, let me tell you, Toronto is a fantastic party city! It's a fantastic place, so I was surprised.
"I think it's a good signing for them. I know that when he went to Toronto, he did extremely well, but he had one or two injury problems, so he didn't play as much as he should have done. I know he did have a problem settling there, as one or two people told me.
"He could have been the big star of the MLS in the eyes of the fans in Toronto. He got something like 11 goals in 19 games. If he had stayed fit, he may have got them into the play-offs. Their form fell away when he got injured.