The Portland Trail Blazers have been dealt a blow after star guard Damian Lillard was ruled out of the Game 5 showdown against the Los Angeles Lakers in the NBA playoffs.

Lillard will miss Wednesday's crucial clash in the Western Conference first round due to a right knee sprain, the Trail Blazers announced on Tuesday.

The in-form Lillard suffered the injury in the third quarter of Monday's 135-115 loss to the Lakers in Game 4, as the eighth-seeded Trail Blazers fell 3-1 behind in the best-of-seven series.

LeBron's Lakers – the top seeds – can seal their spot in the second round at Walt Disney World Resort midweek.

Lillard averaged 30.0 points, 8.0 assists and 4.3 rebounds per game in the regular season, while he was averaging 24.3 points, 4.3 assists and 3.5 rebounds in the playoffs.