Manchester United have made an offer of £34.5million for Ajax defender Lisandro Martinez.
Arsenal have already seen one offer of similar value rejected, but United could inflate their proposal with add-ons.
It is thought Ajax are holding out for a package in the region of £43m for the 24-year-old Argentina international.
United's £13m swoop for Feyenoord's Tyrell Malacia has been complicated after an attempt by the defender to dump his agent.
Malacia remains on course to become new manager Erik ten Hag's first signing but the switch has been delayed because of his unusual decision to change representation midway through the transfer.