The Browns have lost 26-year old starting inside linebacker D’Qwell Jackson for the next 4-8 weeks due to a strained right pectoral muscle in his chest.  Jackson played in 6 games for the Browns last season and he had 59 tackles, 2 tackles for a loss, 2 passes defensed and 1 forced fumble.  32-year old Eric Barton and 23-year old Kaluka Maiava will duke it out in training camp to see who replaces Jackson for the first couple of games.  Barton played in 8 games for the Browns last season and he had 58 tackles, 1 tackle for a loss, he defensed 2 passes and he had 1 fumble recovery.  Barton is a Mangini favorite from their days together with the Jets so he likely has a slight edge right now.  Maiava played in 16 games as a rookie for the Browns last season and he made 45 tackles, had 2.5 sacks, he defensed 2 passes and he forced 2 fumbles.  The Browns hope Jackson heals quickly because he’s better than the alternatives.