Whether Levy would be so willing to sell Son to a Premier League rival remains to be seen .
Wolfsburg are believed to have real competition for Son 's signature -- and their written offer is their first concrete move to win the race for him .
Whether Levy would be so willing to sell Son to a Premier League rival remains to be seen , but Wolfsburg are believed to have real competition for Son 's signature -- and their written offer is their first concrete move to win the race for him .