Terrence Williams’ offseason is not off to a great start after the Celtics player was arrested on charges he pulled a gun on his son’s mother.

The 25-year-old backup guard for the Celtics allegedly brandished a gun Sunday during a visitation exchange with his son’s mother in Seattle, the Associated Press reported. Williams, a native of Seattle, was booked into the King County Jail on Monday on assault charges.

The mother of Williams’ son called police around 1 p.m. PDT Sunday and said the Celtics player pulled out a gun and threatened her. Williams wasn’t around by the time police showed up, but Seattle authorities caught up to him and arrested the backup point guard. Williams and the victim have a 10-year-old son together.

Williams played basketball collegiately at the University of Louisville from 2005 to 2009. The Celtics made him a first-round draft pick in 2009, when Boston selected him 11th overall.

The Boston guard so far hasn’t lived up to that lofty draft selection, averaging 4.6 points and 2.4 assists per game in 2012-2013.

Basketball