Fells and the team agreed to a three-year, $12 million contract, Ian Ropoport reported Wednesday morning.
Even though the Browns have David Njoku and Seth DeValve, Fells should provide the team with much needed help blocking at the position.
Fells, who has started 37 of the 54 games in which he’s appeared, spent last season with the Detroit Lions after playing for the Arizona Cardinals the previous three years.
Fells, listed at 6-foot-7, 270-pounds, totaled 17 catches for 177 yards and three touchdowns last season for Detroit and he has 57 career receptions for 713 yards and seven touchdowns over 4 seasons.
Fells would be the fifth player to agree to terms with the Browns since the open negotiating period began Monday at noon joning offensive tackles Chris Hubbard and Donald Stephenson, defensive lineman Chris Smith and running back Carlos Hyde.
General manager John Dorsey traded for receiver Jarvis Landry, free safety Damarious Randall and quarterback Tyrod Taylor on Friday.