See below from the NFLPA website. All 4 of his seasons have been spent on either active, inactive or injured reserve status.
Accrued Seasons – An Accrued Season is a season during which a player has been on full pay status (Active, Inactive or Injured Reserve List) for six (6) or more regular season games. However, a player who is on the Exempt Commissioner Permission List, the Reserve Physically Unable to Perform/Non Football Injury List, or the Practice Squad for any of the six (6) qualifying games will not earn an Accrued Season regardless of his pay status.