Editor’s note: The Raiders have been right with the salary cap for a few years now. They have roughly $74 million in cap space heading into the start of unrestricted free agency next week. Teams can negotiate with other team’s players on Monday and formally sign them Wednesday. We’ll take a look at how the Raiders could fill several areas of need heading toward the NFL’s free-agent frenzy. The first installment examines offensive linemen.

The Raiders offensive line played extremely well at times but seemed to wear down near season’s end. They operated without Austin Howard then, lost with a knee injury, which sent the formation out of stasis. A discombobulated line suffered some, but most pieces weren’t faulty. They have generally quality personnel, though they certainly need an upgrade at right guard.

There’s some uncertainty at left tackle, where Donald Penn heads toward free agency still untethered, without a long-term deal to keep him home. That may change Sunday or in the hours leading up to 1 p.m. on Monday, when other teams can negotiate with free agents. The team’s view toward free agency will pivot based on Penn. If he leaves, left tackle becomes a top priority. If not, the Raiders can focus on guard and let other spots grow together.

TOP INCUMBENTS

RT Austin Howard: 6-foot-7, 330 pounds, six accrued seasons, Northern Iowa

Stats: 13 starts, 4 sacks, 18 other pressures allowed

LG Gabe Jackson: 6-foot-3, 335 pounds, two accrued seasons, Mississippi State

Stats:16 starts, 1 sacks, 22 other pressures allowed

C Rodney Hudson: 6-foot-2, 300 pounds, five accrued seasons, Florida State

Stats: 13 starts, 1 sack, seven other pressures allowed

Jon Feliciano: 6-foot-4, 325 pounds, one accrued season, Miami

Stats: Three starts, one sack, four other pressures allowed

Thoughts: Penn remains a free agent the Raiders hope to retain. They could upgrade at right guard over J’Marcus Webb, who played there last season. Offensive line coach Mike Tice likes Feliciano, who started late at right guard, but an established upgrade could end up taking precedence. Some of their depth is also in flux, with reserve center Tony Bergstrom and tackle Khalif Barnes set for unrestricted free agency. Matt McCants was offered a restricted free agent tender and could return as a primary backup.

Menelik Watson is recovering from an Achilles’ tendon tear, and could factor into the mix as well.

QUALITY TARGETS

NOTE: There are plenty of free-agent offensive linemen, but we’ll focus on guard upgrades and suggest FA replacements should Penn bolt.

Kelechi Osemele (Ravens): 6-foot-4, 330 pounds, four accrued seasons, Iowa State

Stats: 14 games started, one sack, 20 other pressures allowed

Good fit? This isn’t a good fit. It’s a great fit for the Raiders’ current situation. Osemele ranks among the league’s best guards, but has experience playing quality left tackle. His signing could provide insurance should Penn leave, which could take some pressure off filling the left tackle role with a high draft pick or big splash. If he slides inside and Penn stays, the Raiders would have an elite offensive line. Osemele is a solid fit for many, and could be expensive.

Alex Boone (49ers): 6-foot-8, 300 pounds, six accrued seasons, Ohio State

Stats: 13 starts, three sacks, 14 other pressures allowed

Good fit? Boone has experience playing right guard and could plug in and play well within an established line without having to move from the Bay Area. Boone is an aggressive, physical player who is position versatile and excellent in the run game, where the Raiders need the most help. They would value his skill set and his style of play. Would the Raiders mind his outspoken nature?

Richie Incognito (Bills): 6-foot-3, 319 pounds, nine accrued seasons, Nebraska

Stats: 16 starts, two sacks, 17 other pressures allowed

Good fit? Incognito returned to NFL football with his best season, and proved he is an excellent interior lineman. Incognito is forever linked to the bullying scandal in Miami that kept him out of work in 2014. He’s 33, but could bring greater physicality to the run game. That’s something the Raiders need most, and he could give Feliciano more time to develop and become the long-term option at right guard.

Russell Okung (Seahawks): 6-foot-4, 310 pounds, six accrued seasons, Oklahoma State

Stats: 13 starts, five sacks, 31 other pressures allowed

Good fit? The market for left tackles is sparse, and it could be tough to find a veteran of Penn’s quality. Okung has had some injury struggles but is technically proficient and has experience as a top-end blind side protector. Okung could well stay in Seattle, but he’s one of few options that would give Tice sleepless nights heading forward without Penn.

Other options: Ramon Foster (Steelers), OG Jeff Allen (Chiefs), OT Kelvin Beachum (Steelers), OT Andre Smith (Bengals)

Overall thoughts: The Raiders need help up front, and this personnel department has no fear spending money to acquire blocking talent. That puts Osemele in play, even just as an interior lineman. There are better free-agent options at guard over tackle, with position versatile players like Boone as better options for Tice to mix and match. That creates issues at tackle, which may become a draft issue if Penn leaves. As it stands, he ranks among the top, if not the best, left tackles on the market. Money would be spent wisely keeping Penn and adding a real talent at right guard. That would also allow the team to address defense with top draft picks.