In a court filing Friday, prosecutors said the government doesn't intend to offer evidence that Tsarnaev shot Donohue.
Instead the government alleges Tsarnaev is responsible for Donohue's injuries because Donohue was shot while he and other officers were attempting to prevent Tsarnaev's escape.
Investigators have never said who shot Donohue.
Donohue has said he has no memory of the encounter on the streets of Watertown between police and bombing suspects Tamerlan and Dzhokhar Tsarnaev.
Federal prosecutors are also requesting attorneys for Tsarnaev notify them if they plan to introduce any evidence that Tsarnaev had a mental illness.