The 21-year-old started the game on the bench but came on in place of Clemens Fandrich in the 76th minute.
Luzern remain in forth place in the league despite the weekend defeat with 20 points in 14 games. Marlus Babble’s side take on Sion this weekend.
Yeşil joined Liverpool from the German side Bayern Leverkusen back in 2012 for £1 million.
The Liverpool Echo states that the Merseyside club have decided to send the 21-year-old out to aid his development.
The 21-year-old has featured for all of Germany’s youth teams from Under-16 to U19 and he is available also to play for the Turkish national team.
Luzern sit in forth place in the league with 20 points in 13 games. Marcus Bable’s side take on St. Gallen next weekend.