Moscow's Ostankinsky District Court ruled Monday to subpoena businessman Sergei Polonsky in the trial against media magnate Alexander Lebedev on charges of hooliganism and political hatred.
At a hearing held Monday, Polonsky's lawyers said their client was not able to attend the trial because he was abroad and asked the court to consider evidence given by him at the preliminary inquiry, Interfax reported.
But the judge agreed with Lebedev's lawyers, who said the trial could not continue without Polonsky.
Lebedev pleaded not guilty at Monday's hearing and said he did not understand the charges.
The charges were filed against him in 2011 after he punched property developer Polonsky while the two recorded a television talk show. Prosecutors said his actions were motivated by political hatred.
As an outspoken critic of the Kremlin, Lebedev said the case was part of a broader clampdown on President Vladimir Putin's opponents and Putin's way of getting back at him for criticizing the government.
Soon after the incident, Putin referred to Lebedev's behavior as "hooliganism."
Polonsky also may go to jail. He was detained in Cambodia in January and accused of assault and illegal detention of crew members who worked on a boat on which he had been traveling.
He spent three months behind bars and was released on bail last month.