If he is kept it'll pretty much be based on not being able to get as much for him, mixed with his CL goals. I said at the time and before but he is more useful in Europe as defenders don't get so tight, and are normally leaving more spaces than our domestic opponents. His style takes advantage of that.
In terms of Serie A his record is not impressive at all. 5/9 of his goals came in two games, and only one against a 'big' team (Inter

). 2/4 of his assists came against Pescara, who had the weakest Italian defence since Operation Husky.
1159 minutes
129 minutes per goal
9 goals (Chievo 2, Pescara 3, Bologna, Genoa, Inter, Sampdoria)
4 assists (Pescara 2, Inter, Torino)
In short if he were to leave it would have minimal impact on us in terms of our Serie A campaign.