Milan defender Daniele Bonera will miss the start of the Serie A season after being ruled out for up to three months with a broken kneecap.

Bonera injured his right knee in Saturday's 2-1 victory over Valencia, in a friendly match in Spain.

Tests have revealed Bonera will be out for "70-90 days, barring complications."

The Serie A season starts Aug. 24. Bonera will also miss the Champions League playoffs.

Milan teammate Robinho injured his left thigh and his condition will be reevaluated in two weeks.