Controversial Australian striker Mark Viduka is included in Celtic's squad for the first time when the champions face Dundee United in a vital clash at Parkhead today.
Viduka's team-mate Vidar Riseth believes defenders had better get ready to nurse their bruises.
"Mark is a very strong man, the strongest player I have ever played against," said the Norwegian, who has been employed at the back in the absence of Alan Stubbs.
"I have faced Mark in training and it is very difficult to take the ball off him. He holds it up so well."
Viduka has impressed coach Jozef Venglos with recent displays in the under-21 side. He has scored twice in successive games and is close to full fitness again after his £3 million transfer from Croatia Zagreb.
Venglos said: "Mark is making progress and has been working with the first team. He is in the squad tomorrow and we shall make a decision on whether he plays just before the game.
"He showed improvement in his last under-21 match and looked a lot sharper than before.
"Mark has been working quite well and his understanding with the players is OK. Now he is ready for the next stage."
Old Firm rivals Rangers are not in action until Sunday when they face Kilmarnock at Rugby Park.
