One of the keys for best-ball and dynasty fantasy football leagues is identifying the "inflection points" within the calendar.
An inflection point is a time during the year where a player's value is going to change. For example, when free agency opens, and a team signs a new running back, that's going to have a major impact on the other backs on the roster.
If you had known beforehand that the Denver Broncos were going to sign Melvin Gordon, you obviously would have had a lower valuation on Phillip Lindsay and Royce Freeman and acted accordingly.