TAMPA — The Bucs had plenty of beef in their backfield before Saturday with 250-pound bruiser LeGarrette Blount and 5-foot-10, 223-pound first-round pick Doug Martin.Already, the Bucs had size. On Saturday, they believe they added some sizzle.By drafting Utah State running back Michael Smith in the seventh round, Tampa Bay added the kind of speed it has rarely had. The 5-9, 205-pound Smith said he has run an unofficial personal best 4.26-second 40-yard dash during his predraft training, and ran 4.33 at his campus pro day. That would have matched the fastest time at the NFL scouting combine this year."Every time Mark (Dominik) and I watched tape, he would jump off the tape at you," coach Greg Schiano said. "It's just a different kind of speed than everybody else on the field. How we utilize that is going to be our job. … But speed wins, and this guy brings quite a bit of that."Other teams had an interest in Smith, too. Dominik, the general manager, said another GM called offering a 2013 sixth-round pick for Smith, which the Bucs declined.Smith figures to have a chance to become a change-of-pace back and likely has a good chance to make the roster because of his uniqueness. He'll battle the likes of Mossis Madu, an undrafted prospect who arrived last year from Oklahoma.But Smith doesn't mention speed when asked about his best qualities. He instead stresses his willingness to play a complementary role, something he has been doing for quite some time."Yeah, I'm fast, but I feel like my mental toughness (is greater)," Smith said. "Like I said, I wasn't the starter at Utah State. I had Robert Turbin in front of me. He's a great running back, so I had to seize the opportunity when I got it. So, I believe (I have) mental toughness and not getting down on yourself when things don't go your way."As a backup to Turbin, who was the Seahawks' fourth-round pick, Smith didn't have a chance to be a featured back. But Smith still rushed for 870 yards and nine touchdowns in 2011, averaging 7.6 yards per carry.Smith finished with two of his best games — 121 yards in the regular-season finale against New Mexico State and 157 in a bowl matchup against Ohio.