A Greater Manchester police spokesperson said: "We are definitely not pursuing criminal procedures. We will be taking no further action."
However, the two players could still face FA charges.
"We're awaiting the written reports from the police before we can decide what course of action to take," said an FA spokesperson.
Police clear Hammers duo
At the end of the tempestuous game at the Reebok last season, incidents occurred in the tunnel as the players left the field.