Arsenal reportedly asked Manchester United to include Anthony Martial in any deal to send Alexis Sanchez to Old Trafford during the January transfer window, according to David Woods of the Daily Star.
Woods said the Gunners made the request for France international Martial when United made their initial approach to sign contract rebel Sanchez.
The Chilean is also wanted by the Red Devils' neighbours Manchester City, but Woods noted how interest from United could scupper the plans of the Premier League leaders to add Sanchez to their forward line.
It's looking increasingly likely City manager Pep Guardiola won't be able to reunite with Sanchez after the pair worked together in Barcelona during the 2011/12 season.
BBC Sport's Simon Stone and David Ornstein have reported City are now prepared to miss out on Sanchez, even if it means United signing him instead, due to the demands of both Arsenal and the player's agent.
Stone and Ornstein pointed out how the Gunners want a fee of £35 million for their best player, even though his contract expires this summer. Meanwhile, Sanchez's agent wants an additional payment worth £5 million.
City's reluctance is one more reason United may have the strongest case for signing Sanchez. The other is the idea Red Devils manager Jose Mourinho would include a player going the other way in any deal.
Aside from Martial, Henrikh Mkhitaryan is another attacker United may offer as a makeweight, per ESPN FC's Mark Ogden.
However, Woods revealed there is a third player United are considering letting move to the Emirates Stadium this month: "Mourinho might be able to offer Arsenal an incentive in any deal by allowing centre-back Chris Smalling to go to north London."
Securing a centre-back as experienced as England international Smalling would be a major boost for an Arsenal squad light in defence. Nacho Monreal and Laurent Koscielny are injured, Per Mertesacker is retiring at the end of the season, while Shkodran Mustafi, Rob Holding and Calum Chambers have all struggled.
However, United need the 28-year-old while Eric Bailly deals with injury and Phil Jones remains brittle. Summer import Victor Lindelof is also continuing a tricky adaptation to England's top flight.
Mourinho may feel differently about how much he needs Martial. He's not a regular in the starting XI, often splitting time with Marcus Rashford on the left. Martial has often been substituted, with Mourinho questioning his stamina in late-November, per Charles Perrin of the Daily Express.
However, Manchester Evening News writer Samuel Luckhurst said Martial's recent upturn in form has convinced Mourinho to seek upgrades on the right side of his front three.
Giving up Martial for Sanchez would mean sacrificing a burgeoning talent who is still just 22. Meanwhile, Sanchez is 29 but does offer a stronger guarantee of match-winning displays than a player who is still more potential than end product.