Countdown to Bucs training camp: Offensive backfield 
Fourth-year pro Doug Martin was plagued by injuries each of the previous two seasons. 
Bobby Rainey is a solid ball carrier who also has been adept at catching passes. Tribune staff Published: July 28, 2015 Bucs coach Lovie Smith wants to build his offense around the running game, especially with rookie Jameis Winston likely to start at quarterback. The best way to reduce the pressure on a young, potentially mistake-prone quarterback is with a running attack capable of gaining good yards on first and second downs. Keep in mind, the Bucs are in the NFC South, where reducing the number of times rival quarterbacks Drew Brees, Matt Ryan and Cam Newton have the ball is always among the keys to winning. One of the best ways to do that is to bleed the clock dry by running the ball consistently and effectively.THE BELL COWDoug Martin enters camp as the favorite to be the featured back, but after two straight injury-plagued, sub-500-yard rushing seasons, he’s far from a lock. Martin, a former first-round draft pick, is in the final season of his rookie contract after the team opted not to pick up an option year for 2016. Martin’s biggest threat is probably Charles Sims, a 2014 third-round draft pick who missed the first half of his rookie season with an ankle injury. Also in the mix is Bobby Rainey, a solid ball carrier (94 carries, 406 yards, 4.3 avg.) and pass catcher (33, 315, 9.5), and rookie Dominique Brown, who has the size to be a power back.THE FULLBACKCoordinator Dirk Koetter’s offense calls for a lot of four-receiver sets, which all but prohibits the use of max protection schemes up front and can reduce the number of two-back sets the team employs. But the battle for the fullback spot is still an important one, because Koetter needs a player versatile enough to throw a lead block, catch the ball out of the backfield and make yards on the ground. Rookie Joey Losefa, a 2015 seventh-round draft pick, might be the most adept in those three areas, but he and Evan Rodriguez are new to the position and lack experience. That figures to give Jorvorskie Lane an edge, but the battle could go on all year.BREAKOUT PLAYERThe Bucs drafted Charles Sims last year thinking he might one day develop into a dual threat similar to Matt Forte of the Bears. That’s asking a lot of any player, but Sims has the ability to make a big impact as both a runner and pass catcher. Sims displayed an ability for catching the ball out of the backfield with 19 receptions for 190 yards in eight games last season. But after gaining just 185 yards on 66 carries (2.8 yards per carry) he has to prove he can run more effectively. Though some scouts doubt he’ll develop into anything more than a third-down pass-catcher, Sims is a one-cut runner with the flexibility and quickness to spin off blockers and turn short gains into big ones..CAMP OBJECTIVEFor veteran Doug Martin, the goal is to continue playing at the high level he displayed during the offseason program, when he had many with the Bucs thinking he was on the verge of regaining the Pro Bowl form he displayed as a rookie in 2012. If Martin can do that, he’ll win the job as the lead ball carrier. If not, the search for a true bell cow could rage on well into the season. The situation is similar at fullback. The Bucs would like to see someone emerge as their best option, but with Joey Losefa and Evan Rodriguez learning on the job, it could be a slow process.
