TCU kicked off its spring drills over the weekend. Below is a preview of what to look for from the Horned Frogs during the rest of spring practice:

Offensive returner ready to take next step: Despite backing up B.J. Catalon for half the season, Aaron Green finished fourth in the Big 12 with 922 rushing yards. In five games as a starter following Catalon's season-ending head injury, Green spark the Horned Frogs with his big-play ability, averaging 6.48 yards per carry with six touchdowns. With Catalon leaving early for the draft, Green takes over as TCU's full-time featured back. And playing alongside quarterback Trevone Boykin in TCU's wide-open attack, the former Nebraska transfer could be in for a monster senior season.

Defensive returner ready to take the next step: After playing in the shadows of Devonte Fields and Chucky Hunter the previous three years, defensive tackle Davion Pierson is primed to take command as main man of the TCU defense. Pierson is entering his fourth season as a starter along the Horned Frogs defensive line, and with Hunter graduated, TCU will be leaning on him to supply the leadership and production. If Pierson can fill that role, the Horned Frogs could be stout yet again up front.

Redshirt freshman to watch: Shaun Nixon was the gem of TCU's 2014 signing class, and was set to contend for time in the Horned Frogs' running back rotation until a preseason ACL knee injury forced a redshirt. Nixon has rehabbed his way back and has been participating in TCU's offseason workout program. The Horned Frogs have other backs to flank Green in experienced sophomores Kyle Hicks and Trevorris Johnson. But if he can get -- and stay -- healthy, Nixon has the talent to emerge as Green's primary wingman in the TCU backfield.

Most significant position battle: Graduation completely decimated the Horned Frogs at linebacker. All-American Paul Dawson, starter Marcus Mallet and key reserve Jonathan Anderson, who combined for 266 tackles last season, are all gone. That has basically left the Horned Frogs with a blank slate at the position. The good news is that Gary Patterson has multiple possibilities for replacements. Sammy Douglas, Paul Whitmill and Ty Summers, a converted high school quarterback, will get the first cracks this spring to prove they can man the position. But three-star early enrollees Mike Freeze and Alec Dunham could push them.

Key midterm enrollee: The Horned Frogs need a successor to Kevin White at cornerback opposite Ranthony Texada, with several returning options in Nick Orr, Corry O'Meally, Torrance Mosley and track star/punt return specialist Cameron Echols-Luper, who is moving from receiver to cornerback. But the Horned Frogs are also pumped about the potential of early enrollee DeShawn Raymond, the top signing in TCU's 2015 recruiting class. The Metairie, Louisiana, native had offers from several high-profile programs, including Nebraska, Florida State, Georgia, Arkansas and LSU. And at 6-foot, 185 pounds, he has size to be a factor early in his career.

Question that could be answered: Though they'll have several new faces in the rotation, the Horned Frogs should exit spring drills with a good feel for what the composition of their secondary will be. The cornerback battle opposite Texada could linger into the fall. But Texada and Kindred give TCU a pair of cogs to retool around. And though they'll have to earn their starting spots, Kenny Iloka and Denzel Johnson should be ready for bigger roles after backing up Hackett and Carter last season.

Question that won't be answered until fall: TCU's two-deep could be mostly solidified coming out of the spring. But the Horned Frogs won't know how well its new parts will mesh together until it begins facing potent Big 12 offenses in the fall. Six of the top seven tacklers from last year's defense are gone, including longtime mainstays like Carter and Hunter. TCU has the potential to be formidable again defensively. But with so many new pieces, there could be some growing pains, too.