Stefan Nebel was scheduled to race a KTM in AMA Pro Superbike at Miller Motorsports Park this weekend but isn’t at the track.

According to team sources, the two-time IDM German Superbike Champion encountered a problem with his visa and couldn’t get into the United States.

Professional racers require a specific visa when entering the U.S. to compete in money-paying events.

More details will be posted as they become available.

Update: Mitch Hansen, owner of the KTM/HMC Racing team that Nebel rides for in the AMA Pro Superbike Championship, said: “He [Nebel] did all of the stuff to get the proper visa and not cheat and just be here on a visitor’s visa. Everything was in place. They said they sent it next day air to his home, but it never arrived. And the tracking number they gave him doesn’t come up in DHL’s system. It’s not a good tracking number. He was dealing with the U.S. embassy in Germany, I think.”

Hansen said Nebel still had not received the visa as of today and he was unsure if Nebel would receive it in time to travel to Road America for the June 1-3 AMA Pro event at that track.