Could T.J. Watt one day be the NFL's all-time leader in sacks???
Bruce Smith -- the current sack record-holder -- certainly thinks so ... telling TMZ Sports the Pittsburgh Steelers star is "the one we want to watch now because he's young."
Smith has held the all-time sacks mark since 2003, when he logged his 200th career QB takedown ... and nobody has come close to the number since.
Guys like J.J. Watt and Von Miller -- two of the best of this generation -- barely have over 100, and their careers are winding down.