Player release issues threaten Japan and South Korea's Olympic hopes

Both countries have monopolised the continent's berths at a string of Olympic Games and they will be among the favourites to each claim one of the three guaranteed places on offer in France when the Under-23 Asian Cup kicks off in Doha on Monday.

But, with the tournament played outside dates set aside on the FIFA-approved calendar that requires clubs to release players for international competition, neither nation will be able to field their strongest line-up.

Since 1992 only those aged 23 or under have been permitted to play in the qualifiers for the Olympic Games, while an additional three overage players are allowed to be selected for the 16-team finals in the men's event.

Players such as South Korean winger Lee Kang-in, currently contracted to Paris Saint-Germain, or Real Sociedad's Japanese international Takefusa Kubo are eligible but will not take part in the qualifiers in Qatar because of issues over their release.

The growing global reach of European clubs' scouting networks has seen increasing numbers of players from the region move west, and the impact of that means the competition for Asia's Olympic places is wide open.

Japan and South Korea are not the only nations playing in the Asian qualifiers, which conclude on May 3, to potentially be affected by the unavailability of key performers.

Australia coach Tony Vidmar has been shorn of a glut of players employed by clubs throughout Europe while Uzbekistan, the Asian under-20 champions, could be without Lens defender Abdukodir Khusanov and playmaker Abbosbek Fayzullaev.

That is likely to work in the favour of nations such as Saudi Arabia, the current Asian under-23 champions.

All of coach Saad Al-Shehri's squad are attached to clubs in their domestic Saudi Pro League, which has seen a significant uptick in quality recently because of the influx of foreign talent into the competition led by CristianoRonaldo.

And with eight of the squad that won the title two years ago in Uzbekistan expected to feature again in this campaign, Al-Shehri will be confident Saudi Arabia can secure the country's first Olympic berth since 2020.