Swansea midfielder Pablo Hernandez hopes to end a spell sidelined with injury with a "special" return against former club Valencia.
Hernandez, who missed the 3-0 Europa League win over Valencia in September, has made six appearances due to injury.
He could return against the club where he spent eight years before a £5.55m move to the Swans in August 2012.
"I have trained this week with the team and hopefully I will play," said Hernandez.
"The last three months have been very hard for me.
"I started the season with an injury, but then I played three games and picked up an injury in the international break that followed.
"I made my recovery against West Ham, and then after two training sessions I had another injury which was different to the previous one.
"But to play on Thursday night would be special for me."
Hernandez trained with Swansea this week and manager Michael Laudrup confirmed the Spanish international could make his comeback on Thursday.
Swansea face Group A leaders Valencia knowing a victory would guarantee their place in the last 32 of the competition.
Hernandez, who has been plagued with hamstring and thigh problems this season, has set sights on a "special" return against Valencia.
"This game is very special to me because this is my old team, but for the rest of the squad it is also very important," said Hernandez.
"I missed the first game at the Mestalla but I went to the game with the squad and it was a special night.
"Valencia is my second home. I was there for eight years, and this will be a special game for my family and friends."
Swansea can qualify from the group before they actually kick-off against Valencia.
If St Gallen only manage a draw with Kuban Krasnodar in Russia - in a game which finishes before kick-off at the Liberty Stadium - Swansea are guaranteed a place in the knockout stages.
Valencia currently top the group on nine points with the Swans just a point behind while St Gallen have three and Kuban have two.