Robbie Muirhead has left Kilmarnock to join fellow Scottish Premiership side Dundee United on a three-and-a-half year deal.
A fee of around £150,000 plus add-ons has been agreed for the Scotland Under-19 forward, who is currently 18.
And Huddersfield Town defender Paul Dixon has re-joined his former club United.
The 28-year-old left-back, who has three Scotland caps, left Tannadice for Huddersfield in 2012.
But he has not played for the English Championship side since mid-December.
Dixon, who has made 92 appearances for the Terriers, was due to be out of contract in the summer and the deal at the Scottish League Cup finalists is thought to be for two-and-a-half years.
United sold left-back Andrew Robertson to Hull City last summer, with Conor Townsend replacing him after moving north on loan as part of the deal.
Last week, United allowed right-back Keith Watson to join Hibernian on loan.
Muirhead made his Killie debut in 2013 and made over 40 appearances for the Ayrshire side, scoring four goals.
Meanwhile, United have sent three players out on loan to gain first-team experience in League Two.
Jordan Moore has joined Queen's Park and fellow 20-year-old striker Ola Adeyemo has joined East Fife.
Goalkeeper Marc McCallum, 21, has extended his spell at Arbroath.