One of Chris Ballard's major points of emphasis since taking over the Colts has been clearing out the old veterans on the defensive side of the ball. Mike Adams, D'Qwell Jackson, and Arthur Jones were among those not welcomed back, and six of Ballard's eight draft selections were used on young defensive players.
However, the Colts don't have much at middle linebacker, and David Harris is now available:
#Colts might be solid landing spot for David Harris. Need more stability in second level for weak run ‘D’ and the vet can still play, lead.— Arthur Arkush (@ArthurArkush) June 6, 2017
Harris is 33, but for a one-year rental (or very short, incentive-laden contract) may be a better option than Sean Spence, Edwin Jackson, or Anthony Walker Jr., but it's hard to see Ballard coveting a 33-year old for his rebuilt defense.