This is the fourth in a series of stories that's examining the Packers' roster, position by position, heading into the 2018 NFL Draft. The series continues with the offensive line.

GREEN BAY – One side of the Packers' offensive line is locked down. The other side is loaded with uncertainty.

That's how things stand heading into the 2018 draft for Green Bay, which very likely could add a high pick to one of the competitions brewing on the right side.

The left side is set, with left tackle David Bakhtiari and left guard Lane Taylor holding down the fort. Throw in the contract extension given to center Corey Linsley as the 2017 season wrapped up, and that trio, health permitting, will be the anchor of this year's unit.

The right side could take a number of different forms, though. Veteran right guard Jahri Evans, who started 14 games on a one-year contract last season, remains unsigned. No. 1 right tackle Bryan Bulaga is rehabbing a torn ACL sustained in Week 9, putting his availability for Week 1 in question.

All updates so far on Bulaga's recovery have been positive, but the season opener would be just 10 months removed from the injury, so there's no guarantee.

Furthermore, two candidates to potentially fill in at right tackle until Bulaga returns to full health are coming off season-ending injuries of their own – 2016 draft picks Jason Spriggs (second round) and Kyle Murphy (sixth round).

Spriggs missed two months last season due to a hamstring injury but returned from injured reserve. Then a month later he injured his knee and went back on IR again. The knee injury reportedly did not require surgery, though, and Mike McCarthy has indicated he hopes Spriggs will be ready for training camp.

Murphy got three starts at tackle early last year and acquitted himself well (two on the left side for an injured Bakhtiari, one on the right for Bulaga) before a broken foot ended a potentially promising season in late September.

Another entry in the competition at right tackle could be Justin McCray, a natural guard who played every spot on the offensive line at some point last season except center, though he's trained to play there as well. McCray earned nothing but praise from the coaching staff for his versatility and performance under tough circumstances all season long.

But McCray might have a better chance of winning a starting job at right guard, where fellow undrafted prospect Lucas Patrick also will compete. Patrick essentially played the final two games last season at right guard, after Spriggs injured his knee on the first snap against Minnesota in Week 16 and McCray immediately kicked out to right tackle.

Others looking to get in the mix are 2017 sixth-round pick Kofi Amichia, who spent his entire rookie season on the practice squad, and undrafted prospect Adam Pankey, who was on the active roster beginning in Week 2 but did not appear in a game until Week 17.

All this leaves wide-open possibilities for what the Packers might do in the draft, and the implications their actions could have. A selection at tackle could allow McCray to zero in at guard, while an addition at guard might make McCray a top candidate at tackle, if Spriggs and Murphy are still dealing with health issues.

More depth at center could be on the radar, too, with Dillon Day currently the only pure center backing up Linsley. Day, who came into the league undrafted in 2015, spent the bulk of his first three years on Denver's practice squad before joining the Packers late last season.

The one virtual certainty is the Packers will add to their offensive line room at some point in the draft. Only once in his 13 drafts as GM did Ted Thompson not take at least one offensive lineman, and eight times he drafted multiple players at the position.

Where everyone eventually will line up is for the coaches, with the help of the medical reports, to sort out. Opportunities are presenting themselves, with potentially two starting jobs a long way from being decided.

*PRE-DRAFT ROSTER REVIEW
*WR: Perimeter pass-catchers
QB: Backup competition already in place
RB: Position starkly changed shape