A spokesman for U.S. Rep. Denny Rehberg said that state Sen. Greg Barkus was piloting the boat that crashed into rocks and hospitalized five, including the congressman.
One of the two Rehberg staffers hurt in the crash, state director Dustin Frost, has a serious but "survivable" head injury.
Rehberg friend and former staff chief Erik Iverson said that Rehberg could be released from the hospital as soon as Monday. He said the congressman recovers from ankle surgery, and has a fracture around his eye.
Iverson said that Rehberg's blood alcohol level was .05, but stressed the congressman was not driving the boat. That would still be below the legal limit of .08 for piloting a boat.
Iverson said he has no such information for Barkus, the driver.
Also injured was Rehberg health care policy adviser Kristin Smith, who was recovering from several fractures.
Rehberg, two staffers, a state legislator and another passenger were hospitalized in stable condition Friday after their 22-foot boat ran into rocks in the dark — leaving the vessel perched on the side of a steep outcropping.
"It was a pretty serious accident near Wayfarers state park," Department of Fish, Wildlife and Parks spokesman Tom Palmer said.
Rehberg had surgery Friday afternoon for a broken ankle, and suffered cuts and bruises, his office said. The boat was found fully out of the water, facing uphill on a steep slope of solid rock in an area cordoned off Friday by investigators.
"He took quite a bump on the head," said friend and former chief of staff Erik Iverson. "But he was in good spirits and he was, quite frankly, most concerned with how everyone else was doing."