Dallas Cowboys wide receiver Dez Bryant allegedly hit his mother in the face with his baseball cap ... and grabbed her by the shirt so hard that he ripped her bra ... this according to arrest documents obtained by TMZ.
The docs say ... cops were dispatched to Bryant's mother's home in DeSoto, Texas on July 14 at 1:47 PM after receiving a 911 call reporting an assault -- family violence.
Once cops arrived to the scene, Dez's mom Angela told cops she had gotten into an argument with Dez and demanded that he leave the home ... and that's when Dez got physical.
On the 911 call, Angela says, "My son has assaulted me. He's here now. he won't go home. I keep telling him to go, he won't go." You can clearly hear an argument in the background as Angela says, "I can't let him keep doing me like this. I'm gonna put an end to it today."
According to the documents, cops returned to Angela's home 2 days later and she complained of pain in her wrists, hands and arms ... and said her chest was sore from Dez pushing her.
Cops say they observed bruising in her upper arm. The docs list Dez Bryant as being 6'1", 198 pounds.
Bryant turned himself into police yesterday, and was booked for assault -- family violence, a Class A misdemeanor.
Dez’s attorney, Royce West, tells us ... “We’re going to do an investigation, find out what happened for ourselves. The most important thing is that we heal the family.”