The loss of Johnny Manziel and Ben Malena at Texas A&M opens the door for a pair of returning running backs to make their mark. Implementing new schemes, changing positions and coming back from injury are also what spring practice is about. RBs could supply Aggies with 1-2 punch With so much attention at Texas A&M given to the three-way quarterback competition and the progress of five-star recruit and receiver Speedy Noil, the fourth item on this list bears watching. With Manziel and Malena gone, the Aggies lost their top rusher and their top running back from each of the last two seasons. Manziel and Malena combined for better than 3,500 yards on the ground during that period. While coach Kevin Sumlin wants to continue with a quick-paced attack, the fact that Manziel is not around will likely yield an offense that gets more use out of its running backs regardless of who wins the QB battle. That means Aggies fans might see some thunder and lightning in the form of Tra Carson and Trey Williams. Carson, who will be a redshirt junior with two seasons of eligibility remaining, is a bull (6-0, 230) with good speed. He had only 62 carries last season and missed a couple of games with a neck injury, but he made the most of his totes with 329 yards (5.3 ypc) and seven touchdowns. While Carson can rip off runs up the middle, the much smaller (5-8, 195) Williams is shifty with game-breaking speed. As a sophomore last season that speed was on display during a four-game stretch at the front end of the conference schedule when he totaled 243 yards rushing (7.8 ypc) and four touchdowns. For the season he compiled 407 yards (7.0) and half-dozen TDs. Carson's arrival in College Station two years ago represented a homecoming of sorts. The Texas native followed the footsteps of LaMichael James in going from the same high school in Texarkana to Oregon. As a freshman in 2011 Carson rushed for 254 yards (5.6) in 10 games for Chip Kelly's Ducks, but he grew homesick and transferred to A&M where he redshirted in 2012. Now he and Williams have an outstanding opportunity to be key contributors in Sumlin's offense. Welcoming back familiar faces It is likely nobody looked forward to the start of spring practice March 5 more than Ole Miss coach Hugh Freeze. Taking the field and preparing for 2014 was undoubtedly good therapy following a winter of discontent that brought about more than its share of off-field issues. On the field, one of the concerns coming out of last season was a pass rush that tied for 96th nationally (Mississippi State and Notre Dame) in sacks per game (20). Freeze and defensive coordinator Dave Wommack may already be better off, though, with essentially the addition of two players. The presence of end C.J. Johnson and end/linebacker Deterrian Shackelford could make a big difference when it comes to pressuring the quarterback. Johnson took the field for only four games last season before needing surgery on his right ankle. That was after breaking his right fibula in the spring. After such a trying year Johnson can live with a hamstring that has slowed him so far this spring. (He has also taken to dishing out advice, as he did prior to the Rebels' first practice of the spring.) Johnson, who checks in at 6-2, 237 and will be a senior, earned several second- and third-team preseason SEC honors heading into last fall. That was thanks to a strong sophomore season of 2012 when he recorded a team-high 6.5 sacks and added eight tackles for loss. It was such production that he never had much of chance to build on last year. Shackelford -- he is no longer known as D.T. -- was granted a sixth-year of eligibility by the NCAA in January and opted to return. He missed the 2011 and '12 seasons due to ACL surgeries on his right knee. Though he started only two games last season he played in all 13 and had a pair of sacks while finishing fourth on the Rebels with 7.5 tackles for loss while flip-flopping between end and linebacker. This spring the 23-year-old, who is working on is master's in education, has been working out at linebacker where he still can impact the pass rush. Stepping back to stand up This time of year marks an opportunity to implement new schemes and systems and that is never more true when a new coaching staff is on board. Welcome Vanderbilt's 2014 spring practice. One of the things new coach Derek Mason is installing is a 3-4 defense. As defensive coordinator at Stanford he utilized the 3-4 to take advantage of the athleticism of players that might ordinarily line up at end, but would be better served as outside linebackers -- especially in this era of spread offenses. At Vandy, where a considerable dust cloud has begun to settle with the start of spring practice, Mason feels he has a number of similarly talented players that can adjust in the switch to linebacker. Led by senior to-be Kyle Woestmann, who voiced his approval of the change, three of the unit's top four in sacks a year ago will be among those working at their new linebacker positions this spring. This is all part of Mason's desire to find impact players on either side of the ball during his first spring at the helm of the Commodores. At least as far as the defensive side of scrimmage is concerned the feeling is that he has the players that can make his version of the 3-4 work. Mizzou QB should come down to one guy No doubt competition is a good thing and with five scholarship quarterbacks there is plenty for Missouri coach Gary Pinkel and second-year offensive coordinator Josh Henson to look at this spring. While Pinkel at least publicly is not one to tip his hand about the QB situation, there should be no question that the top job is indeed Maty Mauk's to lose. While his sample as a redshirt freshman last season was not large, Mauk was clutch when replacing the injured senior James Franklin for four games in the heart of the SEC schedule. Coming off a 2-6 showing in their initial season as an SEC member, the Tigers were riding high when Franklin got hurt late in a victory at Georgia, their first road win over a top-10 team in more than three decades.