His common teammates are not Gaudreau and Monahan, nor does he receive a lot of "1st liner" icetime.
Since the first time Hartley tried Ferland in a top 6 role (Dec 22 2015) Ferland has spent 147:00 of his 5v5 ice time with Sean Monahan, and 331:00 away from Sean Monahan.
That is 30.8% of his ice time on Monahan's wing.
Or, "every third game for the last three and a half months"
Additionally, he's spent 120:05 of those minutes away from Monahan, on Backlund's wing.
That totals 54.8 of his 5v5 ice time for that period spent in a top 6 role.
Additionally, he's played 58.2 on the power play since that date. The Flames have played 248.9 on the PP since, so Ferland has been on the ice for 23.4% of the power play time over that span.
But he's not even a third liner.