The Uruguay international has started only four of 12 Premier League matches this season.
Unai Emery says Lucas Torreira he is a very important player for Arsenal, but the 23-year-old must improve his all-round game.
The Uruguay international, who joined the Gunners last summer from Serie A club Sampdoria, has started only four of 12 Premier League matches this season.
Rumours has it that Italian giants AC Milan and Napoli are interested in the midfield marshall - who impressed a lot at the Emirates last season, however, Emery insists that Torreira must 'improve' to help the Gunners.
"He is a very good player, important for us, and his focus needs to be with us 100 per cent," Emery said as the Evening Standard reported.
"He has very big commitment and very good behaviour. He has a very big future here but he needs to improve. He has to learn in some situations, individually to help us, to do better. It's one process."
Emery added: "He played well last year but this year he's not being consistent.
"My challenge to him is to improve, to do better with some tactical issues on the pitch and above all be consistent.
"I spoke with him on Wednesday and Thursday. I showed him some movies about his best performances with us and how he can improve.
"He is young, his process here is starting and he started playing in the Premier League last year and he progressed, but this year again he needs to progress."