Arsenal's pursuit of Arthur Melo is in danger of collapse - with Juventus unable to recruit a suitable replacement in the January transfer window.
Gunners boss Mikel Arteta wants to take Brazil international Arthur on loan until the end of the season, but the deal has hit a stumbling block.
Sources close to Arthur said "the next 24 to 48 hours will be crucial" as all parties try to save the proposed deal from falling through.
Juventus will not let Arthur leave until they can recruit a replacement for him, with Borussia Monchengladbach's Denis Zakaria and Lyon's Bruno Guimaraes on their shortlist.
But until Juve can bring in a new midfield face, Arsenal boss Mikel Arteta must wait on Arthur, 25, with time running out ahead of Monday's transfer deadline.
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Arthur has been a peripheral figure at Juve and came off the bench in Sunday's goalless draw against AC Milan for only his ninth league appearance of the season.
Juve are said to favour an 18-month loan for the former Barcelona star, with the option to buy at the end of that spell.
Should Arsenal miss out on Arthur, it would come as their second major blow in a matter of days after Juventus agreed a fee of €75million (£63m) to sign their priority striker target, Dusan Vlahovic, from Fiorentina.
But the Bianconeri's reluctance to let the player depart on loan unless they sign a replacement is far from the only obstacle giving Arteta and Arsenal technical director Edu a headache.
The Gunners are unwilling to commit to more than a six-month loan for Arthur, even though they held positive talks with his agent, Federico Pastorello, in London last week.
Failure to recruit a midfielder would damage Arsenal's hopes of a finish in the Champions League spots and it could leave Arteta light of options having shipped out numerous players in the January window.
Ainsley Maitland-Niles has linked up with Jose Mourinho at Roma until the end of the season while Folarin Balogun and Pablo Mari have also secured loan exits, to Middlesbrough and Udinese respectively.
Sead Kolasinac joined Marseille after the mutual termination of his contract and there is also great uncertainty surrounding the futures of forward trio Pierre-Emerick Aubameyang, Alexandre Lacazette and Eddie Nketiah.
Arsenal have dedicated a huge amount of time to trimming the wage bill in the hope of January incomings, yet they have just five days to come up with solutions as their swoop for Arthur is at risk of resulting in the same fate as their pursuit of Vlahovic.