That's why there is hidden value gained from a traditional fourth line talent providing surprise scoring punch in a given year. This past season, Ryan White delivered such a season, scoring 11 goals in 73 games, and even earned a deserved spot on the team's second power play unit.
But while goal scoring is an added bonus from a player like White, the most important job of a fourth liner is to provide a breather for the team's true offensive talents and to avoid becoming a liability at even strength. In that area, Ryan White proved far less successful.
http://www.broadstreethockey.com/2016/6/2/11669448/ryan-white-season-review-grade-flyers
tl;dr good room guy, not a 4th line regular.