Stated in Star Trek (2009) movie that Starfleet had the primary bulk of the fleet engaged in the Laurentian system. Was there ever any information why this was?
The bulk of the Federation fleet was supposedly offering support to the Klingon fleet currently in distress. (A bit strange or unusual considering the posture of the Federation and Klingon Empire in the Star Trek: Into Darkness.)
From Memory Alpha:
A deleted scene from the film establishes that the Narada was crippled after it was rammed by the Kelvin. A convoy of Klingon warbirds eventually arrived and captured the ship and its crew. Twenty five years later, Nero and his crew escaped from their imprisonment on Rura Penthe, reclaimed the Narada, used the ship to destroy 47 Klingon warbirds, and continued on their mission.