It can be difficult to become overly bullish on certain fantasy players with OTAs not yet underway, and depth charts four months from being established. Inevitably, players will swing (sometimes wildly) up and down my monthly Top 150 Rankings as we glean meaningful information from practice and beat writer reports. So this is very much a rough draft. A place to start.
As for criteria, keep in mind I place special value on non-quarterbacks I believe will be week-to-week difference makers in head-to-head fantasy matchups. Non-QBs who can swing scoring with monster box-score stats. Hence my aggressive ranking of Rob Gronkowski.