The 31-year old has played 202 AFL games for Sydney and West Coast, winning a flag at both clubs.
Eagles General of Football Craig Vozzo said it was a tough decision parting ways with the veteran.
“It is always a very difficult time of the year that has been made more complex this year due to the uncertainties around AFL list sizes etc. Unfortunately we are not in a position to offer Lewis an opportunity beyond this year,” Vozzo told the club website.
“Lewis has been a highly valued member of our playing group for the last six years and will always be fondly remembered as a Chris Mainwaring medallist and a premiership player.
“We thank Lewis for his contribution to the club and wish him and his young family every success as he moves into the next phase of his life. His vibrant smile and personality will be missed around the place.”