The giant striker is Czech Republic's top scorer with 52 international goals to his name and his fitness will be key to his country's hopes of winning Euro 2008.
Koller suffered a thigh injury in the opening game of the 2006 World Cup against USA and the Czech's went on to lose their next two group games without him.
He is the perfect foil for Milan Baros and scored six goals in 11 games in qualifying, while he was on target twice at Euro 2004, with his striker partner Baros netting five as the Czech's made the semi-finals.
Koller will cause the best defences problems in Austria and Switzerland and his return to goalscoring form is not good news for Switzerland, Portugal adn Turkey.
Although Arsenal schemer and Czech captain Tomas Rosicky has been ruled out of the tournament through injury, there are plenty of familiar names in the Czech squad.
Most obviously - and distinctively in his rugby headguard - is Chelsea's Petr Cech. Firmly established as number one for club and country, he can claim to be the world's top keeper.
In front of him will be David Rozehnal who put aside his struggles at Newcastle to play a key role in the Czechs' qualification. He's now on loan at Lazio, but with doubts surrounding their interest in a permanent deal, this represents a shop window for the centre-half.
Marek Matejovsky could not prevent Reading from being relegated from the Premier League, but he left his mark with a stunning 20-yard strike against Liverpool at Anfield.
Former Liverpool and Aston Villa striker Milan Baros has returned to the Premier League this year with FA Cup winners Portsmouth, and will be keen to repeat his performances of four years ago when his five goals earned him the Golden Boot.
And midfielders Liobor Sionko and Rudi Skacel will be familiar to Scottish fans after spells at Rangers and Hearts respectively. Skacel is currently on Southampton's books, but has been on loan at Hertha Berlin.
