From the video
he plays this role that is kind of awesome for modern fantasy football where he has a higher average depth of target and generates Yak... his role is not going to be diminished. They are not going to stop throwing him the ball... If QJ's drops don't reappear, he's easily worth his ADP... QJ can definitely score 10 touchdowns. I don't think he will, but he definitely can.
STACKED’s take
Secure role with high aDOT/YAC; worth ADP if drops don't return
Johnston's role is secure and will not be diminished; he plays a role that is awesome for modern fantasy football with higher average depth of target and generates yards after catch, making him more likely to generate big plays. Mattek emphasizes the Chargers will not stop throwing him the ball or having him be a huge part of their offense because other receivers like Ladd and Charlie Kolar cannot generate those big plays. Mattek took Johnston at pick 81 in his draft. If Johnston's drops don't reappear, he is easily worth his ADP; however, Mattek notes he is not a huge target earner, which is a limiting factor for his ceiling. Johnston can definitely score 10 touchdowns, though Mattek doesn't think he will; the key with Johnston is how many touchdowns he can score.
Quentin JohnstonWR · LACPlayer page — value, ADP, projections, and every insight