Chicago Bears Ray McDonald -- New Domestic Violence Arrest ... 2nd in Less Than a Year

Former 49ers star Ray McDonald has been arrested in Santa Clara, CA for alleged domestic violence and child endangerment.

There are reports McDonald was taken into custody at the home of his former 49ers teammate Justin Smith. As for the child endangerment -- he and his ex-fiance had a baby earlier this year ... but police haven't said if she or the baby were involved in this incident.

McDonald was also arrested for domestic violence last summer -- and was accused of a sexual assault in December. The D.A. did not file charges in either case, but the 49ers released their star defensive lineman ... saying he'd made "poor decisions."

The Chicago Bears signed McDonald in March.