Melbourne Victory could lose star striker Archie Thompson to a hamstring injury for Saturday night's crucial A-League clash with Brisbane Roar.The 33-year-old left the pitch early in Tuesday's training session, after feeling at his right hamstring, and did not return from the changerooms.A Victory spokesman later said Thompson had complained of tightness but did not feel he had torn the hamstring, although the striker was to undergo further assessment.Thompson, who has seven goals this season, has not scored any in the club's past five games.But fellow attacking player Marco Rojas said Thompson remained enormously important to Victory's set-up and his playing prospects would have a big bearing on the club's hopes."It's very significant. He's one of our best players," Rojas said."Although he hasn't scored for a while, he's still been very threatening and is getting into those positions."He's a great player and a great person to be around as a young player, so he's very important to the team."If Thompson does miss out, it could open the door for Jean Carlos Solorzano to take a starting position against the club with which he won a championship last season.The Victory will be trying to notch consecutive wins for the first time this season when they take on the resurgent Roar at Suncorp Stadium.On Friday night, Melbourne downed the top-placed Central Coast Mariners to give coach Jim Magilton his first win in six games in charge.The Victory are still in eighth spot, two points and goal difference out of the top six.But Rojas said they felt they had made steady progress under Magilton, after the mid-season sacking of Mehmet Durakovic."The confidence and the passing the ball around and the movement, it's just got a bit more fluidity to it," Rojas said."I think everyone can see it's getting better and hopefully we can challenge and get back into the top six."