Complex sentence: The season saw many appearances by Agents Harris and Lane (Marc Macaulay and Brandon Morris), two FBI agents sent to keep tabs on Michael, but were eventually replaced by Jason Bly (Alex Carter), all are in turn removed from Michael's case.
Split into simpler sentences: The season saw many appearances by Agents Harris and Lane (Marc Macaulay and Brandon Morris), two FBI agents sent to keep tabs on Michael. They were eventually replaced by Agent Bly (Alex Carter), who in turn was removed from Michael's case.