With spring ball a month away, we've been ranking position groups in the Big 12. These evaluations are based on past performance, future potential and quality depth. We continue this series with offensive line:

1. Baylor: All five starters return for the Bears, notably All-American left tackle Spencer Drango, who spurned the NFL draft to return for his senior season. The majority of the entire two-deep, in fact, is back, as well, including right guard Desmine Hilliard, who missed much of last year with a wrist injury. Despite being a two-year starter, Hilliard will have to fight to reclaim his starting job, as Jarell Broxton slotted in nicely in place of him during the second half of the season. This unit has a superstar in Drango, plenty of experience and a ton of depth.

2. TCU: The TCU offensive line was among the most-improved units in the league last year, setting the tone up front for the nation's second-highest scoring offense. Left tackle Tayo Fabuluje is gone, but the rest of the unit returns intact, including center Joey Hunt and right tackle Halapoulivaati Vaitai, who were both second-team All-Big 12 performers in 2014.

3. Texas Tech: Texas Tech encountered all kinds of problems last year, but offensive line wasn't one of them. All-Big 12 left tackle Le'Raven Clark was terrific protecitng the blindside of quarterbacks Pat Mahomes and Davis Webb, as Tech allowed only one sack per 43 pass attempts, which was among the best rates in the country. Center Jared Kaster and guards Alfredo Morales and Baylen Brown will all be three-year starters.

4. Oklahoma State: The Cowboys were dreadful along the offensive line for much of last year. But the group rapidly rebounded late, due in part to the healthy comeback of Zachary Crabtree at right tackle. Crabtree will be able to stick on the right side, too, thanks to the mid-semester arrival of transfer Victor Salako, who started two years for UAB and is expected to man left tackle for the Pokes. Oklahoma State also should be deeper overall with junior college transfers Brandon Pertile and Matt Kellerman joining returning starters Michael Wilson, Jesse Robinson and center Paul Lewis. Mike Gundy still needs to hire a position coach for this group with Bob Connelly bolting for USC.

5. Oklahoma: The Sooners were hit hard by graduation with longtime lynchpin tackles Daryl Williams and Tyrus Thompson both departing. Center Ty Darlington is back; so is veteran guard Nila Kasitati. Oklahoma also signed the nation's No. 1 juco guard, Jamal Danley, to play alongside them. Tackle is the big concern, but the Sooners are hopeful that either Orlando Brown Jr. or Kenyon Frison will be ready to step up after redshirting last year.

6. Kansas State: B.J. Finney was a four-year fixture at center for the K-State offensive line and will be dearly missed. But the Wildcats return the rest of the offensive line, including standout left tackle Cody Whitehair, who should take over for Finney as group leader. The Wildcats need guard Boston Stiverson to make a full return from the leg injury he suffered in the Valero Alamo Bowl. They also need more consistent pass protection from their right tackles.

7. Texas: The Longhorns got better up front as the season wore on, but this is still a unit with a bunch of questions. Left guard Sedrick Flowers was the only linemen to start every game, as Texas tinkered with six different combinations over the course of the season. Center Taylor Doyle and right guard Kent Perkins should retain their starting gigs, but junior college transfers Brandon Hodges and Tristan Nickelson, as well as early enrollee freshman Connor Williams, all have a chance to overtake Marcus Hutchins, Camrhon Hughes and Jake Raulerson at the tackle spots.

8. Iowa State: Left tackle Brock Dagel missing most of last season with a knee injury could be a silver lining for the Cyclones in 2015. Jake Campos got valuable experience along the line, including left tackle. As a result, the Cyclones should be in good shape on the bookends, provided Dagel is 100 percent. Guard Daniel Burton is one of the more underrated players in the league. Cole Anderson and Kory Kodanko, who both redshirted last year, have a good shot of joining the rotation.

9. West Virginia: The Mountaineers weren't great up front last year, and now they've graduated their two best blockers in guards Quinton Spain and Mark Glowinski. Tyler Orlosky bring stability on the inside at center, but tackles Adam Pankey and Marquis Lucas need to take a step forward in their second seasons as full-time starters.

10. Kansas: The Jayhawks don't have any difference-makers up front, at least not yet. But Jacob Bragg, one of the top center recruits in the country last year, has a chance to become one in time. Joe Gibson and Junior Visinia return along the interior. So does rising senior tackle Larry Mazyck, who may be asked to swing to the left side.