Rand Paul that broke the lawmaker's ribs.
Boucher's felony conviction is punishable by up to ten years in prison.
A June 15 sentencing date for Boucher has been set, with federal prosecutors looking to give him a 21-month prison sentence.
The Nov. 3 incident between the two men left Kentucky's junior senator with broken ribs and led to Paul being treated for pneumonia.
His attorney Matt Baker says the retired physician is ready to put the ordeal behind him.More news: London jobless rate rises amid labour force surge
Boucher has agreed to pay an undisclosed amount to Paul as restitution.
"He is anticipating acquiring an entire determination", Baker said. A friend of Paul's said the senator had gotten off his riding mower to remove a limb when he was tackled from behind. Paul has said he never saw the attacker because he was facing downhill and wearing ear protection from the noise of his lawn mower. When the U.S. Attorney's Office charged Boucher in January, it said Boucher had signed a plea agreement.
In comments to police, Boucher indicated the attack was not politically motivated, according to court documents.
Boucher, who is Paul's neighbor, admits the fight was about yard maintenance.
"I stress it because so frequently with these types of cases you see people accidentally coming together and they may not even mean it, and things might happen", Battani said to Boucher.