adrian peterson (grimmace)Whoa! This is not a good look for Adrian Peterson.

Peterson has become the king of the baby daddies all of a sudden.

According to a TMZ report, the NFL running back fathered a 4th child … a 3-month-old girl. The mother is said to be a waitress at a popular Minnesota nightclub.

Sources say the child’s last name on her birth certificate is listed as “Peterson.”

On the day Peterson’s 2-year-old son Tyrese passed away, the mother of his 4th child posted an emotional message on her Facebook page about the situation.

“Today has been a long day finding out my [daughter”s] brother passed away and knowing that she never even got to meet him.”

Sources connected to the situation tell us … the mother of AP’s 4th child first met the NFL star while serving him as a VIP waitress at a place called Seven — a steakhouse, sushi joint and ultralounge all wrapped in one.

It’s unclear how involved Adrian has been in the child’s life — but the mother recently posted a photo showing the child decked out in Minnesota Vikings gear, so we’re guessing they’re cool.

In case you’re keeping track, Peterson is the baby daddy of three other children: A 6-year-old daughter, a 2-year-old son and another 2-year-old son, Tyrese Robert Doohen, who Peterson found out about a couple of months ago and only met the day before he died of injuries allegedly inflicted by his mother’s boyfriend.

UPdate …

USA Today is reporting that South Dakota’s State’s Attorney Tom Wollman said the investigation of Joey Patterson, the man charged in the death of Tyrese Robert Doohen, the 2-year-old son of Adrian Peterson is ongoing and that he doesn’t expect to file new charges until the probe is complete, perhaps early next week.

“We are continuing to gather reports at this point,” Wollman said Tuesday.

Little Tyrese was pronounced dead on Friday, two days after Patterson, 27, called to report a choking in the south Sioux Falls (South Dakota) apartment they shared with the boy’s mother.