Massimo Maccarone's move to Siena is in the balance, with Middlesbrough yet to deliver the relevant paperwork to the Serie A club.
The Italian striker's agent claims the player has reached an agreement over a four-year deal with the Tuscan outfit, but the free transfer still requires some red tape to be completed before Wednesday's deadline.
'We are awaiting one document from Middlesbrough for the deal to be completed,' said the player's agent Paolo Fabbri.
'It's unlikely to arrive today, but we hope that it arrives no later than Wednesday. Otherwise, the situation will be complicated - and Massimo would have to return to Middlesbrough.
'Massimo is currently at his house in Italy, waiting for the go-ahead to travel to Siena.'
The 27-year-old joined Boro in a club record £8.15million transfer from Empoli in 2002.
He has made 102 appearances for the Barclays Premiership club, scoring 24 goals, but has failed to hold down a first-team spot at the Riverside this season.