Brentford have signed Blackburn defender Jack O'Connell for an undisclosed fee.
The 20-year-old, who has played most of his football in the past 12 months on loan at Rochdale, has agreed a deal until 2018 at Griffin Park.
He made 45 appearances for Dale last campaign to help them win promotion to League One, and returned this season.
"We are delighted to secure another very talented young player," said Bees boss Mark Warburton.
"Jack is a player who has significant development potential left in him. He fits the profile of what we look for when bringing a young player in to the club."