Kroy Biermann Seen For First Time Since Son's Sexual Battery Arrest

Kroy Biermann has been spotted for the first time since his eldest son was arrested for sexual battery ... and he looked to be handling some business on his phone while picking up one of his sons from football practice.

The former NFL linebacker was seen picking up his 14-year-old son Kash from practice on Saturday ... and, while standing with him, he kept an eye on his phone and a look of concentration on his face.

As we reported ... Kroy Biermann Jr. was arrested by cops earlier this week after a girl from his school accused him of assaulting her inside a gym changing area in April.

She claims Kroy Jr. suggested they go to a co-ed sauna together ... with cops saying she told them he assaulted her in a family changing room, allegedly forcing her mouth on his penis and digitally penetrating her vagina.

He was arrested for alleged aggravated sodomy and aggravated sexual battery.

Kroy Jr.'s mom, Kim Zolciak, blasted the claims in a statement to TMZ, insisting her son is innocent -- and claiming he even passed a polygraph test.

She adds the alleged victim has made "similar allegations involving two other people, which raises serious concerns that deserve to be carefully examined." Her claim about the alleged victim has not been verified.