Steve Lomas has warned he will only let Francisco Sandaza leave St Johnstone in January if the deal is beneficial to his club.
Sandaza has scored 12 goals in 17 games in all competitions this season, but is out of contract at McDiarmid Park at the end of the campaign.
The 27-year-old has been linked with a move to Rangers, should the reigning champions sell Nikica Jelavic, but Lomas is reluctant to lose the Spaniard in the New Year.
Lomas said: "If somebody wants Fran in January it will have to be beneficial for us. It's as simple as that.
"It's got to be right for the club, or else we wait until the end of the year."
Lomas hopes Sandaza will focus on scoring goals for St Johnstone for the remainder of the current campaign before seeking to move elsewhere.
The Saints boss added: "I've said to Fran score 25 goals this season and you can go wherever you want."
Midfielder Murray Davidson has been the subject of repeated speculation in the past 12 months, while the future of other Saints players is sure to be a regular topic of conversation over the next month after their strong start to the season.
Lomas added: "Everyone's under contract until the end of the season, at least.
"I've got no pressure to sell. It would have to be decent offers and it would have to be beneficial for St Johnstone."