With free agency approaching (March 14), we're analyzing the quarterback position on the Titans:

2018 cap hits of top returnees:

Marcus Mariota -- $7.7 million (fully guaranteed)

Matt Cassel -- $2.5 million (non-guaranteed)

Alex Tanney -- $555k (non-guaranteed)

Pending free agent: Brandon Weeden

Key stat: Mariota became the first Titans QB to throw for 3,000 yards in consecutive seasons since Steve McNair in 2002-03. He also became the fifth QB in NFL history to throw for at least 9,000 yards and rush for 900 yards in his first three seasons. But the franchise hasn't had a 4,000-yard passer since Warren Moon in 1991.

Money matters: The Titans are enjoying the luxury of having a franchise quarterback still in his rookie deal. Although Mariota's cap number is rising, he's way underpaid given his production.

Tennessee will be able to spend big in other areas while Mariota remains cheap, but a long-term extension that could make him the NFL's highest-paid QB should come within the next year and a half.

Big picture: General manager Jon Robinson is confident he has his quarterback of the present and the future. The Titans hit on Mariota with the No. 2 overall pick in the 2015 NFL draft and, despite his injury concerns, they aren't looking for anyone to compete with him.

But in Year 4, they are hopeful he can take that next step to be a top-10 QB.

What they will seek this offseason is a reliable and capable backup quarterback to fill in if Mariota has to miss time. This is an underrated but important need, as Mariota hasn't yet played 16 games in a NFL season. Matt Cassel no longer has the skillset to be the top-end QB2 that they need to win if pressed into action.

The game plan: Offensive coordinator Matt LaFleur and quarterbacks coach Pat O'Hara will spend significant time with Mariota this offseason reworking his mechanics and honing in on the fundamentals needed for more consistent quarterback play. Mariota has rare talent and athleticism, but his footwork and pocket feel were out of whack last season. It resulted in a shaky Year 3. That needs to be fixed.

Tennessee will also work to build an offense that perfectly fits with his skill set after placing him in a run-heavy, old-school offense in his first three seasons.

Robinson will evaluate the free agency, trade and draft markets to seek options for a QB2. Appealing options or good fits who could be available include Josh McCown, Tom Savage, Matt Moore, Trevor Siemian and Riley Ferguson.