Kendrick Bourne was not a top prospect coming out of college. He wasn't even the best wide receiver at tiny Eastern Washington University; that would be Cooper Kupp, who was drafted in the 3rd round by the Los Angeles Rams and racked up 869 yards in his rookie season.
But Bourne and Kupp were the most productive receiving duo in FCS history, and both shined as NFL rookies despite the leap in the competition that they faced. After nearly getting cut over being late for a practice, Bourne knuckled down (with extra coaching from Niners coaches Mike Lafleur and Katie Sowers) and became a reliable target, especially for Jimmy Garoppolo in the last five games.