In the last decade or so, the NFL has found amazing value in tough, undersized WRs that run crisp routes and have great hands. Whether or not they can win a jump ball or beat an opposing DB in a footrace is almost irrelevant to the position they play.
Wes Welker was the original example of this, formerly cut by the San Diego Chargers and then turned into a star with the Miami Dolphins and New England Patriots. Since Welker’s retirement, Julian Edelman has been the best example of this, although Cole Beasley has settled into a similar role with the Dallas Cowboys.