Despite scoring just six goals in 15 Italian League matches so far this campaign, Blues boss Sarri believes the 31-year-old can end his side's struggles in front of goal.
The London Evening Standard are reporting on Wednesday that Sarri has once again asked the Chelsea board to try and seal the signature of Higuain.
"This deal is complicated as when Milan took him on loan from Juventus, they paid a £16million loan fee and agreed to buy him outright for £32m in the summer".
'He has to make a decision and take on his share of the responsibility, ' Leonardo said at a press conference on Tuesday.More news: Mattia Binotto to replace Maurizio Arrivabene at Ferrari F1
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"But with all the rumours, there is no point in me thinking about these different situations until we have something to answer".
Higuain played under Sarri at Napoli in 2015-16, and enjoyed the most productive season of his career with 38 goals in 42 games.
"We want to continue to take the club forward and the team forward, and to do that, we've got to keep our best player".
"What we do know is that Chelsea absolutely - I won't say desperate - but they really, really need a striker".
A swap deal involving former Juve striker Alvaro Morata, the Spaniard who is out of favour at Stamford Bridge, has been mooted.