Editor's note: Tony Grossi covers the Cleveland Browns for ESPN 850 WKNR.

The most overlooked need of the Browns in this transaction season is a starting left tackle.

It’s easy to see why it’s overlooked. They haven’t needed a starting left tackle for 11 years, since they drafted Joe Thomas from Wisconsin No. 3 overall in the 2007 draft. People want to believe that Thomas will play forever.

But the Thomas era – a remarkable study in individual excellence against utter team ineptitude – essentially is over.

Maybe not quite officially, mind you.

Thomas is preparing to inform the Browns of his decision whether to retire or return for a 12th NFL season. I think Thomas will retire, and that sentiment has nothing to do with Thomas seemingly working on a second career as a podcast co-host and multi-media football analyst this winter.

I thought 2017 would be Thomas’ last season even before his unprecedented NFL streak of 10,363 consecutive snaps played was snapped – along with his left triceps tendon -- on Oct. 22.

Long before that injury, Thomas spoke frankly and openly of the difficulty he had in recovering physically from Sunday games. He said it was taking him until Thursday or Friday to be able to do the things he needed to do to play at his long-established elite level.

During his subsequent rehabilitation of the triceps, Thomas has said it would not be that injury that ends his career; rather, it would be the debilitating back and knee injuries that have reduced him to one hard day of practice per week for the last several years.

So, I think Thomas will announce his retirement soon. And even if he doesn’t, if he decides to stagger through one more year, the Browns know they must locate Thomas’ successor in this draft or in the veteran market.

No in-house candidate: Spencer Drango exceeded expectations as Thomas’ temporary replacement over the final nine games. But it would be foolish to bank on him as a permanent left tackle.

Remember, the Browns will be adding two new quarterbacks – a veteran and a rookie drafted in the first round – and there must be faith that the left tackle position will not be a weakness. Drango is a fine swing guard-tackle, but to project him as a full-time starter at left tackle is wishful thinking.

Shon Coleman completed his first season as a starting right tackle, and was OK. Auditioning him at left tackle would only impede his growth at right tackle and possibly weaken two positions.

Two young tackles on the roster – Roderick Johnson and Zach Banner – are not candidates to start in 2018.

So the priority is there to find a left tackle who can not only play to a dependable level, but also to start – probably immediately.

Whom will it be?: There is a significant dilemma inherent in this search for Thomas’ successor.

Consider that Thomas, for one, consistently has said that he believes that college offensive tackles are not adequately equipped to play the NFL game as rookies. He said that the proliferation of spread offenses in college leaves the typical college left tackle unexposed to the blocking schemes he will need to master at the NFL level.

Thomas has said that a typical drafted lineman – no matter how highly taken in the draft – needs to sit for a year, or two, before he can start in the NFL. Like quarterbacks, there are exceptions, Thomas has asserted. But Thomas believes only exceptional prospects – preferably from a Big Ten school -- should be expected to succeed immediately as NFL rookies.

Further, the Browns are trying to add experience to their team after two years of being “too young to win.” Starting a rookie at left tackle would be contrary to that endeavor.

NFL Network’s Mike Mayock recently listed his top five offensive tackles in the 2018 draft in this order: 1. Mike McGlinchey, Notre Dame: 2. Orlando Brown, Oklahoma; 3. Connor Williams, Texas; 4. Tyrell Crosby, Oregon; 5. Martinas Rankin, Mississippi State and (tie) 5. Kolton Miller, UCLA.

NFLdraftscout.com lists an additional two players projected to be drafted by the second round. They are: Chukwuma Okorafor, Western Michigan; and Brian ONeill, Pittsburgh.

Now here is the dilemma facing the Browns: The veteran market for offensive tackles is not good this year.

Other than Nate Solder of the Patriots, most of the free agents in the tackle market – and projected salary cap casualties – are either right tackles or swing guard-tackles. These include Chris Hubbard of the Steelers, James Hurst of the Ravens, Andre Smith of the Bengals, Bryan Bulaga of the Packers, Zach Strief of the Saints, and Jared Veldheer of the Cardinals.

So the Browns may have no better choice than to draft an offensive tackle relatively high in the draft and hope he can adapt quickly to try to fill Thomas’ big shoes.

Either that, or hope that Thomas’ back and knee issues subside and persuade him to make one last lap on his way to Canton.