The Saints and Hammers wanted the Czech international this summer.
Now it has emerged that Hoffenheim have won the race for his signature. The talented defender becomes the second player this summer to reject the Premier League for Hoffenheim, following in the footsteps of Fabian Schar. Kaderabek has signed a deal until 2019 with the Bundesliga outfit.
Kaderabek is a 23-year-old right-back, a position which appealed to both Saints and the Hammers. West Ham are to lose Carl Jenkinson in the summer, as his loan deal from Arsenal comes to an end. Meanwhile Southampton are concerned over the future of current right-back Nathaniel Clyne.
The powerful runner has been in great form this season and after being a regular at youth level for the Czech Republic at youth level he has become a fully fledged international in the past year. He currently has seven caps and one goal for the Czech Republic since making his debut against Finland last May.