Thomas has made nine appearances for the Hoops this season as he finds game time hard to come by.
The 24-year-old joined the west London side in 2020 after being released by Leicester, with his contract set to expire in the summer of 2023.
It has been reported that Pompey are looking to bring the Welsh international in on loan for the remainder of the season.
Along with the Tangerines, the Blues are said to have approached QPR over the players’ availability ahead of a short-term move this month.
As mentioned, match action has been hard to come by for Thomas, who has tallied just 83 minutes of Championship football this season.
Meanwhile, he has completed the full 90 minutes on just two occasions this term – both in the EFL Cup.
The Welshman has appeared three times for the national team while racking up 32 appearances at youth level for his country.