West Bromwich Albion have rejected an offer from Chelsea for 16-year-old midfielder Isaiah Brown.
The England Under-17 international, who became the second youngest-ever Premier League player in May, has already begun training with the Blues.
"We are more than prepared for the matter to be decided by a tribunal if needs be," said Albion sporting and technical director Richard Garlick.
"We've invested a lot of time and money in Isaiah's development as a player."
Capped at two levels
- Isaiah Brown has three England Under-17 caps and two for the Under-16s, having scoring his first goal at that level in a 4-3 friendly defeat by Germany in February.
Under Football Association rules, Albion would be due compensation for Brown as he is under the age of 24.
"We are disappointed by Chelsea's offer," added Garlick. "As one of our most exciting Academy products in recent years, we had hoped to bring him through into our first team. But Chelsea have forced our hand.
"More importantly, it makes you question why these young players are joining bigger clubs when they are likely to gain more first-team opportunities in the Premier League at clubs similar to us."
Peterborough-born Brown, reportedly also an Arsenal target, was on scholarship forms with Albion, having been at the Hawthorns for three years.
He was aged just 16 years and 117 days and still at school when he made his first-team debut as a substitute
in the 3-2 home defeat by Wigan Athletic on 4 May.
This is bettered only by Matthew Briggs, who was 16 years and 65 days when he made his Fulham debut in 2007.