SIOUX FALLS, S.D. (AP) — A former Chicago White Sox minor leaguer who went on to coach a South Dakota youth team after his playing career ended has been charged with sexually assaulting a child and possession child pornography.

Juan Thomas Jr., a first-baseman and right fielder who rose as high as Triple-A, was charged Wednesday in Lincoln County, South Dakota, with one count of raping a child younger than 13 and 10 counts of child porn possession. Thomas, 48, pleaded not guilty to the charges, the Argus Leader reported.

It’s unclear how Thomas is connected to the child, said Lincoln County State’s Attorney Thomas Wollman, who asked for the public’s help in identifying any other possible victims.

“We are looking for individuals who know Mr. Thomas and may be able to assist in identifying potential witnesses or victims,” Wollman said.

The White Sox drafted Thomas in the 10th round of 1991 amateur draft, and he went on to be a four-time minor league All-Star, hitting 303 career home runs in 14 seasons of pro baseball. He rose as high as Triple-A, playing for the Seattle Mariners’ top affiliate, the Tacoma Rainiers, during the 2001 and 2002 seasons.

In 2004 and 2005, he played for the Sioux Falls Canaries, a team in the North Division of the American Association of Independent Professional Baseball, which is not affiliated with Major League Baseball.

He later became involved in coaching youth baseball in Sioux Falls, serving as an instructor for a suburban baseball program.

Thomas’ attorney, David Stuart, didn’t immediately reply to a call from The Associated Press seeking comment.