Southampton are believed to have entered the race for Polish left-back Michal Karbownik.
Celtic and Tottenham Hotspur are both said to have expressed an interest in the Legia Warsaw player.
The Sunday Mail reported in May that Celtic were keen, with Leeds United and Barcelona also mentioned in connection with the 19-year-old.
Polish website Sportowe Fakty says Southampton are hoping to sign Karbownik, who is valued at £8.9m.
They say that no offers have yet been received, but the player's agent has previously indicated interest from Celtic and other clubs.
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As quoted in Record Sport, Mariusz Piekarski said in May: "Celtic? I don't really think that is an option for Michal.
"Yes, there is interest there, but he also has many, many big clubs looking at him too.
"I don't want to talk about interest from Barcelona because there is nothing concrete, but there have been from other clubs. There are some top teams who have watched him."
Former Celtic star Chris Sutton, meanwhile, has called Leigh Griffiths "unprofessional" after the striker was left behind in Glasgow to work on his fitness while Neil Lennon's men travelled to France.
Speaking in Record Sport, Sutton said: “Everyone knows the hard yards you need to go through in lockdown – there are no excuses. It was vital to maintain focus and stay on top of fitness.
“The players would all have had programmes.
“It’s just stupid. Neil Lennon will feel let down. If I was a team-mate I’d feel hacked off.
"Griffiths had a huge part in Celtic winning the title. He got a lot of credit the way he came back from his problems and rightly so.
“To have fitness issues at this stage though is just unprofessional."
