He wants to. Davey wants him to (mainly I assume because the team's lefty power is up to Ankiel, Espinosa's bad side, and LaRoche who slugged about .023 last year), Rizzo might not but seems to be warming to the idea. But a year of Bryce now is likely a year less of Bryce down the road.
I'm sure you'd do it if you could have Jason Heyward's first year for Bryce, but I'm also sure you wouldn't do it if you'd follow up with Heyward's second. Jason had more impressive AA numbers than Bryce. Could another year of seasoning prevented the fall back and what was essentially a wasted year at best?
I don't think we can answer these questions, or at least we can't do it better than the guys watching him play everyday. His minor league stats suggest he can hang in the majors, but do you want him just to hang or do you want him to thrive? Rizzo seems to lean toward thrive. He's the type that wants his young players to force the issue in each league before moving up. Bryce hasn't done that just yet.
Looking from the other side, the Nats could certainly use Bryce and are on the cusp of being in the WC race wihtout needing luck. A ROY type year from Bryce would surely put them square in WC contention, rather than the... not "outskirts"... maybe "suburbs", where they are now. It could also help him get acclimated for next season when we all expect one more big move to go from WC to division crown challengers.
And we still haven't talked about the elephant in the room, that just a couple months of minor league time now would ensure a whole season more before arbitration and save the Nationals millions of dollars.
Based on the situation and your gut, what say you? If Bryce looks good, but not great, in Spring Training, do you want the Nats to bring him up to start the year?