Smith played college ball at Alabama before being drafted by the New Orleans Saints in the third round of the 2001 NFL draft, where he started 10 of 30 games accumulating 69 tackles and 4.5 sacks.
He stayed there until 2004 before moving onto the Oakland Raiders for one season where he was placed on injured reserve.
He was out of football during the 2006 season but signed to the Tampa Bay Buccaneers in March of 2007 where he lasted a little over a month being released days after the 2007 draft.
He spent the 2007 offseason with the New England Patriots before being released. He later signed with the Patriots the following offseason, where he was placed on injured reserve for the season.
The Patriots released him in June of this year.
Injury prone? Let's break this down: IR for the '04, '05 and '08 season. Out of football during the '06 and '07 season.
The Chiefs do not have an open spot on the active roster but one could guess that Barry Richardson will move back down to the practice squad, where there is an open spot.
(H/T cah05 for the link)