Sunderland will have to pay an extra pounds 300,000 to Newcastle if they return to the top flight, and a further pounds 200,000 will be due should Sunderland qualify for European competition while Clark, who signed a three-year contract, is on their books.
"Moving from Newcastle to Sunderland doesn't bother me.If you are a bricklayer, all you want to do is lay bricks," Clark said. "And as a footballer you don't want to sit about waiting for somebody to fall ill."
Sunderland made a second signing yesterday, with Chris Byrne, a 21-year- old striker, moving to Roker Park from Macclesfield. He was out of contract but Sunderland have paid a nominal fee to the Vauxhall Conference champions.
Oyvind Leonhardsen has completed his pounds 4m transfer to Liverpool from Wimbledon. The 26-year-old midfielder has been on the brink of the move for several weeks.
Scott Booth has left Aberdeen after nine years to join Borussia Dortmund. He earned himself a three-year contract with the European champions by impressing them in a spell on trial. The Scotland striker is out of contract so Aberdeen, who will receive no fee for a player once rated at pounds 2.5m.
Booth, 25, will join up with his fellow Scot, Paul Lambert, who played in Dortmund's victory over Juventus last week having gone to Germany from Motherwell in similar fashion. Bolton lost interest in signing him earlier this season after watching him in action.
Middlesbrough have dismissed reports of a pounds 12.5m bid by Atletico Madrid for Juninho.Reuse content