O.J. McDuffie. He was building a very solid career from 1993 to 1998, constantly improving his yards per year and averaging about 12 yards per catch and 7 TD's a season. In 1998, he even led the NFL in receptions with 90 but somehow did not make the Pro Bowl even though he was one of the best WR's in the AFC that season. Even with a career high 90 receptions and 1050 yards with 7 TD's, he never registered on the ballot. Then he developed Turf Toe and it ruined his otherwise solid and promising career at what was most likely the halfway point.

Interesting side note on Juice, he is an avid and very talented bowler and was even recorded bowling a 300 game (The video is on YouTube)

As a fan, I'm still a little sore on his 1998 omission.