ROR is a good player, but a little overrated. He's a 2nd/3rd line center making $7.5M/year. According to this fantasy ranking he is ranked 166.
Fantasy top 250 rankings for 2018-19
This is a projection based on playing with a better team and his usage.
He is in the Jeff Skinner/Brendan Gallagher zone. These rankings take into account goals, assists, +/-, penalty minutes, power play points and shots on goal.
There are players on this list ranked higher that I wouldn't take over ROR, but there are players on the list ranked lower that I would take over ROR.
It's interesting to note other Sabres ranks...
Eichel - 33
Dahlin - 71
Risto - 120
Reinhart - 138
Hutton - 150
Mitts - 224