Alonzo Castro is an ancillary character in Scott Sigler’s novel The Rookie. Castro is a rookie starting linebackers for the Texas Earthlings a team which met the Ionath Krakens in the all-important semi-final round of the GFL Tier 2 Tournament. Castro is one of the few successful Purist Nation Players in the Galactic Football League.
Castro first met Quentin Barnes in the PNFL championship having previously played with the Sigurd City Norsemen. Castro again met Quentin just before entering The Combine; This was a bit of foreshadowing as they would meet for the third time when the Earthlings met the Ionath Krakens in the GFL Tier 2 semi finals.
During his time with the Sigurd City Norsemen Castro finished the season leading the PNFL in tackles. A little small for a linebacker, Castro is said to hit with force of an asteroid. During the GFL Tier 2 semi finals, Castro shows his ability one-on-one against Quentin when Quentin is pushed into the tailback slot after the death of Mitchel "The Machine" Fayed. Despite the Earthlings' loss, Castro's performance is one of note as so few Purist Nation Players succeed outside the PNFL.