Sometimes the holes on a NFL roster can be difficult to spot, with depth issues showing up late in games, inexperience manifesting in penalties or a simplified playbook, or a key injury here or there completely changing the dynamic of a team.
Or, sometimes, there's just a big, giant 300-plus pound hole that obviously needs to be filled.
Thursday, on the first day of the NFL's new league calendar, the Chargers made a big move toward filling that hole, agreeing to a four-year deal with offensive tackle Russell Okung.
The contract is worth more than $50 million with $25 million guaranteed, according to multiple reports.
Okung, a former first-round pick of the Seattle Seahawks, Pro Bowl player in 2012 and Super Bowl champion, spent last season with the Denver Broncos. He'll be asked to protect Chargers quarterback Philip Rivers from the left tackle spot.
After missing time with injuries sporadically over his career, Okung, 29, played in all 16 games with the Broncos last season.
The Chargers headed into the off-season with a massive need on the offensive line, and middling reviews for the incoming class of blockers meant free agency would be the quickest path to improvement.
But, unsurprisingly, the Chargers weren't the only team thinking this way.
Detroit, Cleveland, Carolina and the Rams were among the teams that made key signings along the offensive line, boosting prices and urgency for teams such as the Chargers with easily identifiable needs.
Okung's deal with the Chargers comes with some controversy. Because Okung acts as his own agent, teams couldn't speak with him or his advisors about deals until Thursday afternoon when the free-agency period officially began.
But 9News.com reporter Mike Klis from Denver tweeted "industry sources believe Chargers may have tampered with" Okung. Pro Football Talk's Mike Florio reported that teams and agents suspected the Chargers were speaking with Okung's advisor, former agent Jimmy Halsell. If conversations about Okung occurred prior to Thursday, it would be in violation of league rules.
The Chargers probably aren't done with moves up front. The team released starting guard D.J. Fluker this week, and Okung's signing makes King Dunlap's situation with the team even more perilous. Dunlap, who was arrested this off-season, could be cut in an effort to create more room under the salary cap.
In the opening moments of free agency, the team announced they'd reached deals with backup quarterback Kellen Clemens, , long snapper Mike Windt and starting safety Jahleel Addae.
In bringing back Clemens, the team keeps a familiar face in the quarterback room with Rivers. Clemens has been the veteran's backup since 2014, throwing only 10 passes. He has made 21 starts over his 11-season NFL career.
The Chargers also tendered restricted free agents wide receiver Dontrelle Inman (second-round tender) and linebacker Korey Toomer (fifth round). Inman became one of the team's most productive receivers last season, setting a career high with 58 catches and 810 yards. Toomer, signed off the Oakland Raiders' practice squad, also had a nice season, appearing in 13 games and making eight starts.