Sydney - A heartbroken Matt Toomua has vowed to return a better player next season after a ''freak accident'' ended his Super Rugby campaign and left him in tears on Saturday.

Toomua's worst fears were confirmed after the Brumbies' 29-26 loss to the Sharks when scans revealed he would need a reconstruction on his left knee. But he said it was just a coincidence he ruptured the anterior cruciate ligament in the same knee he strained medial ligaments in last month.

The injury comes as Toomua was on the verge of signing a new deal to remain in Canberra. The 22-year-old playmaker had been in negotiations with coach Jake White and hoped to have a contract to remain with the Brumbies finalised in the coming weeks.

He is now likely to have a reconstruction, which could keep him sidelined for nine months.

''I saw a gap and thought I would have a crack and felt my knee buckle under me,'' Toomua said yesterday. ''I'm shattered, especially at the start of the year when you feel like you're onto something special as a team.

''It's disheartening to know I'm not going to be a part of it on the field. I was in tears for quite a while [on Saturday night]. It's frustrating, but in 2013 I'm still 23 and I'd like to think I have years ahead of me. Plenty of good players have had serious injuries and come back.''

Toomua fell to the ground in pain in the 48th minute of the clash with the Sharks. He attempted to step off his left foot, but what he thought was a try-scoring chance ended his bid to be the Brumbies' permanent No 10.

After spending the first four years of his career as an apprentice to Christian Lealiifano and Matt Giteau, he was given a chance to be the first-choice flyhalf this year.

Toomua's momentum was halted when he strained his medial ligament against the Cheetahs and he missed two matches. And his comeback game turned sour when he felt a ''weird'' pain in his leg.

''It's completely unrelated [to my medial ligament], it's just a coincidence that it was on the same knee,'' Toomua said.

''The knee had recovered and they tested the ligaments straight after and they said the medial was fine. It wasn't a case of rushing back, it was just a freak accident.''

Toomua has already sought advice from Brumbies backs coach Stephen Larkham about dealing with long-term injuries. He backed Toomua to become a dominant player when he returns next year.

''It's all right to be sad,'' Larkham said. ''I said that you take positives out of every circumstance that comes out in life. It's all part of the growing and learning experience.''