French champions Paris Saint-Germain on Friday left Kylian Mbappe out of the squad for a pre-season tour of Japan, casting further doubt on the star striker's future.

PSG gave no reason for the omission of France's captain.

The 29-player squad that flies east on Saturday will include Mbappe's younger brother, 16-year-old Ethan Mbappe as well as the club's remaining superstar Neymar.

Mbappe has been taking part in the club's pre-season preparations and played the last 30 minutes as PSG entertained Le Havre in a training-ground friendly on Friday, scoring a goal.

Mbappe declared in May that he would not extend his PSG contract, which expires next year, but indicated he wanted to remain at the club for a final season.

"I still have a year left on my contract and I am going to honour my contract," he said.

That would allow him to become a free agent next summer and leave PSG for nothing.

PSG president Nasser al-Khelaifi reacted by saying earlier this month that Mbappe "must sign a new contract."

"We can't let the best player in the world today leave for free. It's impossible," Khelaifi said.

Even though there has been no confirmation from PSG, some local media reports suggest that the French club, who are confident that Mbappe has already agreed a deal to join European giants Real Madrid for free next summer, have put the 24-year-old forward on the market for sale on the ongoing transfer window. 

According to a report from ESPN, PSG are considering never playing their star forward again. 

Sources told ESPN that Mbappé, who was told the news on Friday after their win over Le Havre, was surprised by the move but has accepted it.

"Players who don't want to be here, the door is open," ESPN wrote that Al-Khelaifi told the squad on Tuesday without naming the French prodigy who was present in the room.

However, Mbappé will not change his mind and sign a new deal. He repeated that stance once more to the club earlier this week, which further angered Al-Khelaifi and the Qatari owners and likely led to the decision to exclude him from the touring squad.

The club are under new management with Luis Enrique as coach.

Their Asian tour opens against Cristiano Ronaldo's club Al Nassr of Saudi Arabia in Osaka, on July 25. PSG then play Cerezo Osaka, also in Osaka and Inter Milan in Tokyo before finishing off the tour in Busan, South Korea, against Jeonbuk Motors on August 3.

Mbappe joined PSG from Monaco in August 2017 in a 180-million-euro ($196-million) deal and has gone on to establish himself as one of the world's most prominent players.