Silva (14-2, one no contest) was suspended for one year by the Nevada State Athletic Commission after submitting a fake urine sample one day before his Jan. 1, 2011, bout with Brandon Vera.
He defeated Vera by unanimous decision. The result of the fight, however, was later changed to a no contest because of Silva's failed prefight test.
Silva was originally scheduled to face Vera in a rematch May 15, but the Norfolk, Va., native withdrew last week with an undisclosed injury.
Pokrajac (24-8) has won two fights in a row. During his most recent outing, he registered a first-round knockout of Krzysztof Soszynski at UFC 140 in December.
Franklin McNeil covers mixed martial arts and boxing for ESPN.com. Follow him on Twitter at www.twitter.com/Franklin_McNeil.