He's playing on the OL anyway. That risk isn't going to change. The point is that if you
add to his OL load some DL plays you're increasing the total risk.
And, IMO, given the overall quality of the non-Sitton roster on the OL, that just sounds like playing with fire to me. Not as bad as putting him on KO teams, but still an extra risk that makes sense.
Its like saying, well, QB is a bigger risk of injury than LB, so its okay to play Aaron Rodgers a couple reps at ILB in addition to his QB duties.
IMO Sitton is, after Rodgers, arguably the second most important offensive player right now. (in the sense of there being a major problem if he gets hurt).
And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.
Romans 12:2 (NKJV)