Brentford full-back Moses Odubajo has completed a £3.5m move to Hull City.
The 22-year-old has agreed a three-year contract with the former Premier League club, who activated the release clause in his deal with the Bees.
Odubajo only joined Brentford last summer from Leyton Orient and went on to make 49 appearances, initially at right wing.
However, an injury to Alan McCormack in October saw Odubajo move to full-back, where he had played earlier in his career.
He kept his place in the defence when McCormack returned to fitness and his impressive performances helped Brentford into the Championship play-offs.
Bees head coach Marinus Dijkhuizen said: “He will be a big loss to us, especially at this stage of pre-season.
“We did not want to lose him, especially to a rival team in our division. However, this will give a chance to another player.
“We have a lot of quality players and enough quality in the squad that we are ready to face Ipswich tomorrow [Saturday].
“We will now be looking to get a replacement in to build our squad back up.”