Lucas Biglia is on his way to the Lazio pre-season training camp, but negotiations continue with Milan offering €17m to the €20m request.
The Argentina international had been given a few extra days off to help push through the move, but now the deadline has expired and he must start training.
Biglia is due to arrive at the camp for his medical tests this evening.
Talks continue, as Mediaset Premium and Sky Sport Italia claim the offer on the table is €16m plus €1m in performance-related bonuses.
Lazio have lowered their original asking price to €20m including bonuses, but want €17m as the fixed fee.