The Mirror claim that Pompey boss Harry Redknapp will launch a £2.5million offer for the Blues centre back when the transfer window opens in the new year.
Newcastle United and Tottenham have also been linked with Upson, who returned to first team action two weeks ago after eight months on the sidelines with an Achilles injury.
Somehow, I think it will take a much bigger offer than that mentioned for Blues to part with Upson, who's present contract at St Andrew's expire's at the end of the season.