Mata will be out of contract at the end of next month and the 33-year-old Spaniard is in talks with the club over his next move.
Mata has only made seven appearances this year and was given compassionate leave before his mother passed away at the end of March.
But Solskjaer insists that the final decision will be left with Mata, a £37.1million signing from Chelsea in January 2014.
"I've kept the dialogue with Juan and we're due to speak again very soon," said the United boss.
"Of course he's not played as much as he would like and that's a decision we will make with him.
"He's in charge of his own future, he's been such a good servant for the club. But it's hard to leave good players and good people out of the team, and it's about what does he want as his next step in his career.
"Is it to play his career out here or is it to go somewhere else? We haven't made the final decision yet."