It's an interesting one. Why not give him a go for the "easier" games?
Maybe one line of thinking, is that with Steward, he's always running forward to contest for the ball after a kick. I think it actually leaves us defensively exposed and pulls the backline out of shape trying to cover for that gap on a quick counter when hes not yet back in position. It also suggests maybe we wont kick as much, but I highly doubt that.
I hope Furbank goes well. I like Steward and hes great in the air, but it feels like he is a one trick pony. He isn't fast enough off a standing start, and defensively can be iffy.