The Italian is halfway through the three-year deal he signed with Southampton in the summer of 2014.
Pellè has been linked with a move back to his homeland in recent days, but Koeman says the issue of the player’s future is not up for discussion.
“Graziano is totally involved in Southampton,” the Saints boss told the media on Friday afternoon.
“Of course I read also the newspapers and what happens on the internet but that’s your business – my business is to prepare the team for [Saturday’s game against West Bromwich Albion].
“Graziano is a player for Southampton. I know it’s left one season on the contract but it’s too early now to talk about his future.
“Okay, the situation of Graziano is a little bit different than other players because he will be 31 [in July] and 32 at the end of next year – and that’s difficult.
“We like to keep every good player in the team and 31 is a good age to still play on your level.
“He had some physical problems with his knee in the last few weeks but it’s going better and it’s important he is coming back and scoring and being the important player what he was before.”