A Football League tribunal has instructed Brentford to pay Walsall an initial sum of £325,000 for forward Will Grigg.
The Bees signed the Northern Ireland international during the summer after his contract expired at the Banks's Stadium.
However, with Grigg being under the age of 24 and the two clubs being unable to agree a fee, the issue was dealt with at a tribunal, with Brentford also being ordered to pay a number of add-ons.
Walsall are due £30,000 for every 20 appearances that Grigg makes up to a total of 100 matches, while they will also receive 20% of any future fee.
Brentford would also have to pay the Saddlers £50,000 if they earn promotion to the Championship, with an extra £250,000 required should they reach the Premier League.