As the Seattle Seahawks continue to wade through the second wave of free agency, one need stands above all others: left tackle.

Russell Okung has met with the New York Giants, Detroit Lions and Pittsburgh Steelers. He has offers on the table, but has apparently not found one yet that has blown him away. If Okung ends up signing elsewhere, the Seahawks will have to shift their attention to another option.

There are two other established, quality starting left tackles on the market: Donald Penn and Kelvin Beachum. Penn turns 33 next month, but has been extremely durable. Beachum is 26, but coming off of an ACL injury.

The Seahawks have cap space available and will likely focus this week on landing one of those three left tackles. But what happens if they're unsuccessful?

The big picture has to be considered here. Their window to win a Super Bowl is wide-open, and the core of the roster is under contract. The defense is loaded with talent and has led the league in fewest points allowed for four straight seasons. Russell Wilson took another giant step in his development, going on a 24 touchdown/one interception tear to end the 2015 season.

Keeping all that in mind, general manager John Schneider and Pete Carroll appear committed to going into 2016 with as few question marks as possible. That doesn't mean sacrificing the future, but it does mean taking calculated risks. And one move that could fit that description is trading for Cleveland Browns left tackle Joe Thomas.

Joel Corry of CBSSports.com brought up the possibility over the weekend:

Thomas would be upgrade at left tackle for the Seahawks, who have the 26th-overall pick in the upcoming draft and haven't kept their first-round pick since 2012. Seattle could restructure his contract after a trade to make it more cap friendly for this season if necessary. Thomas should consider forcing his way out of Cleveland through a holdout if he asks to be traded and the Browns refuse to move him.

Thomas is on a reasonable contract, and he's signed through 2018. He's 31, but still playing at a high level. A trade would not factor into compensatory picks like signing free agents does, and Thomas would give the Seahawks an All-Pro left tackle as they try to figure out the rest of the offensive line.

The Browns were reportedly close to trading Thomas to the Denver Broncos in November in exchange for a first- and second-round pick. Cleveland was giving up a fourth in the deal but reportedly also wanted a third back.

Its management has said all the right things about wanting to keep Thomas, but such comments should be taken with a grain of salt.

In the next few days, the market for free-agent left tackles will likely reveal itself. If the Seahawks are unable to agree to terms with Okung, Beachum or Penn, it may be time to strongly consider another option: prying Thomas away from Cleveland.