The 19-year-old's future is currently the subject of much speculation, with both Arsenal and Manchester City said to be interested in bringing him to the Premier League.
West Ham United are also believed to be keen on his signature, with the teenager impressing since arriving from Danish side Midtjylland in January 2023.
Diomande has made 24 appearances for Sporting, scoring three goals and registering one assist, including two goals and one assist in seven appearances this term.
A recent report claimed that the Ivory Coast international has no interest in leaving the Portuguese giants at this stage of his career.
Neves has now confirmed that Diomande is committed to remaining at Sporting, but he has denied that any talks have taken place over a possible new contract.
"[Diomande] is extremely satisfied at Sporting," he told A Bola. "He is very focused on the club and their objectives for this season, which include winning the league title. And he knows that Sporting is the ideal club for this evolution.
"He will be happy to sit at the table with Sporting but so far there is nothing [to discuss]. Sporting is Diomande's present and future, he wants to evolve but there is nothing regarding [a contract] renewal."
Diomande made a strong impression on loan at Portuguese club Mafra in the first half of the 2022-23 campaign before making the move to the Green and Whites.
Arsenal boss Mikel Arteta is believed to be an admirer of the teenager, while there have been claims that Man City manager Pep Guardiola is pushing to bring him to the Etihad Stadium.
Sporting have made a strong start to their 2023-24 Primeira Liga campaign, picking up 16 points from six matches, which has left them at the top of the table.
Ruben Amorim's side also recorded a 2-1 win over Sturm Graz in their opening match in the group stage of the Europa League.
Sporting remain a hotbed of talent, with the club famously selling Cristiano Ronaldo to Manchester United in 2003, while Bruno Fernandes, Manuel Ugarte, Nuno Mendes, Raphinha and Nani are also among the players to have spent time with the club.