Sonny Bill Williams has been ruled out of the Rio 2016 rugby sevens tournament after injuring his left ankle in New Zealand's shocking 14-12 opening loss to Japan.

The highest-profile player involved in rugby's return to the Olympics after 92 years, Williams did not get up after being tackled just after half-time on 9 August and was helped from the field.

Sonny Bill Williams hobbled off the pitch, favouring his left ankle (Photo: Getty Images/David Rogers)

New Zealand Rugby later said Williams had a partial Achilles tendon rupture and would be replaced for the remaining five games in the tournament by Sione Molia.

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Williams appeared frustrated and was quickly assisted from the field without meeting the press following the end of the match. The biggest name in rugby had ambitions of Olympic gold, and the untimely injury may open the door a little wider for the hopeful Fiji side.

A number of spectators rushed to a small balcony adjacent to the stands in the hope of catching a glimps of the injured athlete in the players' area. 

Williams, a two-time Rugby World Cup winner with the All Blacks in 15s, had limited impact in the opening men's match against an under-rated Japanese team. 

Williams was carted off, looking thin-lipped (Photo: Getty Images/David Rogers)

New Zealand play Kenya later today (9 August) at 5:30pm local time and meet Great Britain tomorrow (10 August) at 12:30pm.