SYDNEY (Reuters) -Wallabies prop Taniela Tupou admits his performances this season have not been up to scratch and concedes that he might not make the Australia squad for the British & Irish Lions series in July and August.

The powerful Tongan-born tighthead moved to the New South Wales Waratahs for this season after the demise of the Melbourne Rebels but has been relegated to the bench after turning in a series of disappointing displays in Super Rugby.

"I really think it's mental, because the performance is not there and I start to second-guess myself, and start asking questions. 'Can I do this? Is this for me?' Or, 'am I good?' You start playing in your head," Tupou told the Sydney Morning Herald.