According to ESPN.com's John Keim, Williams appeared on The Team 980 on Thursday and called Foster's arrest "small potatoes" in comparison to what some people in "high places" have done.
Williams said the following about his comments Friday:
"I want to apologize to the organization, my wife, my mom, my sisters and the six daughters that I have. The last night or so [has] been real tough on me from an emotional standpoint, because never in my life did I say anything so insensitive as [what] I said. I'm not going to sit here and make excuses because there is no excuse.
"There's not a lot to say. No more than the fact that, if you know me, you would understand, growing up, I understand the climate and what's going on. For me to make comments like I did, I want to apologize to anybody out there within earshot, especially the ladies of this area, across the country. Like I said, I got six daughters that no way in the world I would tolerate anything like that. So for me to say something like that, I just want to apologize."
Foster was also arrested in February on suspicion of domestic violence against Ennis and possessing an assault rifle, but the domestic violence charge was dropped after Ennis recanted her allegations. Foster pleaded no contest to the weapons charge and received two years probation.
Per Keim, both those inside and outside the Redskins organization were unhappy with Williams' comments regarding Foster from Thursday.
The 24-year-old Foster was selected by the 49ers with the No. 31 overall pick in the first round of the 2017 NFL draft out of Alabama. Foster recorded 29 tackles in six games this season prior to his release.
Foster is currently on the commissioner's exempt list, meaning he can't play or practice for the Redskins.