Derby County have completed the signing of defender Valentin Gjokaj for an undisclosed fee from Swiss side Lucerne.
The Swiss centre-back has spent the last three weeks training with the Rams and impressed during a handful of pre-season outings.
The 18-year-old has put pen-to-paper on a two-year deal with the Rams, with the option of a third year, after coming to an agreement to part company with Lucerne, who play in the Swiss Super League.
Manager Nigel Clough said: “We have all been really impressed with Valentin since he initially joined the club on trial, so much so we quickly made the decision to sign him up but this deal has taken some time due to the fact this has been a transfer from overseas.
“He will play a big part in the newly-formed under-21 squad and he certainly has the potential to get better, and we believe he can after seeing plenty of him in the last few weeks both at Moor Farm and in game situations.
“It’s another signing which adds depth and strength to the central defensive area of the team and Valentin has also shown he is more than capable of adjusting to life in the English game.
“Already we’ve seen him learning off the likes of Richard Keogh and Jake Buxton, which is very pleasing to see.”
Gjokaj could be included in the first-team squad for today’s npower Championship opener against Sheffield Wednesday at Pride Park Stadium, after international clearance was received late on Friday.