Sirro was a walkup start for our backrow last year. This season this is not guaranteed. Competition for his backrow spot, plus the fact that the other starting backrowers ARE guaranteed a spot, should result in Sirro having a breakout year. If it doesnt eventuate for him in 2018, I doubt it ever will.
He should also benefit from playing alongside Jake and Thompson, based on their experience, workrate and determination. If that doesn't happen, and his "stats" don't measure up in 2018, he will be moved back onto the bench.