TAMPA — The Vikings running back was on his way to a touchdown, stumbling inside the 5-yard line, when Bucs linebacker Khaseem Greene tracked him down in last Saturday's preseason opener.In one motion, Green's right arm flew back and punched the ball, and it popped loose. As the two players flew into the pylon, the ball bounced forward and out of the back of the end zone. It wasn't a touchdown but a touchback for the Bucs, all but taking points off the scoreboard for the Vikings."As much as we preach 'Strip the ball, tackle the ball,' that was a perfect example where it was a violent takeaway, and that's what we are looking for," coach Lovie Smith said.Short of a defensive touchdown, the most valuable currency in a Lovie Smith defense is a takeaway. Perhaps the most positive aspect of the Bucs' 26-16 loss in Minnesota was Tampa Bay's defense forced and recovered three fumbles."It was really sweet," said Greene, 26, a 2013 fourth-round draft pick of the Bears who was claimed by the Bucs after he was waived in the spring. "The objective when we get out there is to get the ball back to the offense. I was just trying to make a play, and I saw an opportunity."The Bucs' big news this week was rookie Kwon Alexander taking over as the starting middle linebacker, with free agent signee Bruce Carter now challenging Danny Lansanah at strongside linebacker. In that shuffle, Greene is getting a long look as the second-team middle linebacker."Now we've worked him at the 'Mike' position, which we feel like is his best position," Smith said of Greene, 6 feet 1 and 241 pounds. "We think his strong suit is playing against the run. That's why we played him. … He's physical, and that was a great play on the goal line."Greene is one of five linebackers battling for the last one or two linebacker jobs. Backup linebacker jobs are often decided by special teams play, and three of the veterans in the competition have solid special teams histories: Larry Dean, Orie Lemon and Jason Williams. Undrafted rookie Josh Keyes is working as the No. 2 weakside linebacker."My mind-set is making the team," said Greene, who had 38 tackles in two years with the Bears. "I got waived. Those things happen in this business. I'm not sour about it, not mad. I'm excited with another opportunity. It definitely motivates me. This is the game I've dreamed of playing my entire life."Takeaways are nothing new for Greene, who was Big East defensive player of the year in 2012 as a senior at Rutgers, where former Bucs coach Greg Schiano converted him from safety to linebacker his junior year. Greene had six forced fumbles as a senior — three in one game — and scored two touchdowns recovering fumbles.The best way to make a case for a spot on the final roster is making plays in games, and Greene has another chance Monday in his first home game with the Bucs, at night against the Bengals. Greene knows Raymond James Stadium from his Rutgers days, winning twice there, with 10 tackles as a senior in a game there.Greene loves the way the Bucs embraced him and other waived players, including safety D.J. Swearinger and his old Rutgers teammate tight end Tim Wright. Tampa feels like home for him, and for it to stay that way, he knows he needs to continue coming up with big plays and takeaways."We've got to get the ball," Greene said. "That's something that's in the front of my head, not only me but all my teammates."