'He is slowly coming round and recognised his father and some friends when they visited him,' said Carmelo del Giudice, the medical director at the Turin hospital where the 24-year-old Italian international is being treated.
'There should be nothing to prevent him from returning to football but please don't ask me when,' del Giudice said.
The hospital said in its latest medical bulletin that the condition of the player, who fractured his skull near his eye socket and had been in a light coma, had improved during the day.
Lentini, who joined Milan from Torino for around pounds 13m last year, a move greeted by Torino fans with violent street demonstrations, was injured when the Porsche he was driving went off the road on a bend near the small town of Villafranca d'Asti, just east of Turin. The car ended up in a ditch and burst into flames.
Lentini was found on the road by a passing lorry driver who took him to hospital in nearby Asti before he was transferred to Turin.
'Our hearts are in our mouths,' the Milan president, Silvio Berlusconi, said. 'I send my best wishes to Lentini and hope that with his strong constitution he will recover quickly and be able to play again.'
The accident happened as Lentini was returning home after playing in a pre-season tournament in Genoa.