What about the next 4 games after that where he averaged 18 and a half minutes and had no production?
In the 18 game stretch I'm referring to, he averaged 17:41 a game and had 4 points to show for it. He had another 16 game stretch where he had 2 points. He finished the final 13 games with 3 points averaging 17:47 per game. That's more than half the season with just 9 points. All this said, doing snippets by game log really doesn't help prove much.
I watched him all season, it's perfectly fine to admit he struggled because he did. He was far from alone. He still somehow managed a 20 goal season, which is why I feel as though if he can round his game out while getting consistent linemates as you mentioned, he'll be fine. I'm not that worried about him because I think he plays with a really high motor, and that's the exact type of style I want to see him continue with. Just get stronger to win more battles and be willing to shoot more.
Looking at snippets of games coupled with partners tells us a tremendous amount of how erratic he was used...
Mercer played as much time this season with McLeod as he did with Hughes... Haula I believe was his most common partner...
You can look at the game logs and see his production increased with more time...and I think it's safe to assume that bigger minutes was with better players, at least partially.
His best stretch of games was early November to the beginning of December he had 9 points in 10 games.. Mercer was playing with Jack and Toffoli for some of this time. He averaged 18:26 during that time. This exactly coincides with Meier being out
The very next set of games December 5th to December 17th...2 points in 7 games averaging 15:08....this exactly coincides with Meier coming back in.
That shit went on all season. With injuries and back filling. And I don't think anyone was moved around more than Mercer.