Mario Williams is off the hook after he was arrested for blowing up in a garage in a tense standoff with his baby mama ... TMZ Sports has learned prosecutors just dropped the case against the ex-NFL star.
The former Houston Texans' No. 1 overall pick got into a heated argument with the mother of his child in the garage of her Texas-area home on Aug. 20 ... and the 34-year-old was hauled off to jail shortly after.
In video of the altercation, obtained by TMZ Sports, you can see a clearly frustrated Williams going off on the woman .