Former WSBK number two Chris Vermeulen was again unable to complete Assen's races on Sunday.

Queenslander Chris Vermeulen’s return to World Superbike competition was again cut short at Assen overnight, ruled out once again on race day due to his troublesome knee injury.

Vermeulen, a three-time WSBK winner at Assen, finally gridded up for the first time in 2011 in race one and was in a point scoring position on his Kawasaki before severe cramp forced him to retire.

His concerns were of a more physical nature as he continues to recover from knee surgery, but the Sunshine Coast resident was at least able to circulate at a decent pace.

“My leg just cramped up and I had to stop after a few laps,” said Vermeulen. “My pace was not so bad and I was holding down a points scoring position but I just could not get to the end.

“This is the first time I have been able to feel the bike really working, and I made some set-up changes because I was pushing at a decent level sometimes this weekend.

“I am happy with what the team has done but we have a lot of work still to do, just because I am a long way behind my team-mates in learning the bike at present.

“I think I should be ready for a full weekend of racing at Monza.”

Earlier in the weekend, Vermeulen had managed to qualify in 18th position.