 His work with BBC Scotland was cited as his reason for not accepting the role of assistant manager at Dumbarton.Ferguson is the elder brother of Barry Ferguson, who also played for Rangers and Scotland in the same position.The siblings played against each other on three occasions during the 1998–99 season while Derek was with Dunfermline, with 20-year-old Barry scoring at East End Park and 31-year-old Derek making his last appearance at Ibrox.