The Seattle Seahawks moved on from a pair of franchise cornerstones this month when they traded Michael Bennett two days before releasing Richard Sherman.

The speculation has since turned to another longtime defensive stalwart, Earl Thomas.

Though CBSSports.com reported last week that the Seahawks are talking to multiple teams about a possible trade, ESPN previously reported that Thomas is more likely to receive an extension than he is to be dealt, according to a source, and that Seattle had been listening to offers for the All-Pro free safety as opposed to actively shopping him.

But what should the Seahawks do?

Here are some reasons why it would make sense to trade Thomas and some reasons why it wouldn't.

Earl Thomas has been named a first-team All-Pro three times and second-team All-Pro twice in eight seasons. AP Photo/Butch Dill

The case for trading Thomas

It's all about the draft picks they might be able to get for Thomas, the money they wouldn't have to pay him and the potential for the situation to go south if, hypothetically, they were to hang onto Thomas but weren't able to reach an agreement on a new deal this offseason.

The Seahawks are without picks in the second and third rounds, having given them up in their trades for Sheldon Richardson and Duane Brown, respectively. After their first-round pick, No. 18 overall, they aren't scheduled to choose again until No. 120, and of their eight selections in all, six are between the fifth and seventh rounds.

The Seahawks are especially low on draft capital at a time when their roster needs an infusion of young talent as badly as it has since the early years of the Pete Carroll-John Schneider regime. There's still a very solid core of players to build around, but consider all of the recently created holes.

Cornerback is a big one following Sherman's release. Defensive line is another. Seattle traded one starter (Bennett), lost another in free agency (Sheldon Richardson) and a third (Cliff Avril) might never play again because of a neck/spine injury. The career of strong safety Kam Chancellor also is in jeopardy because of a neck/spine injury.

And that's just on defense. The Seahawks also have lost two offensive starters in free agency -- tight end Jimmy Graham and No. 2 receiver Paul Richardson. They've made moves aimed at replacing those players, but their offensive line is still in need of an upgrade or two.

Though trading Thomas would create another void and even further diminish the talent on Seattle's defense, it could bring back valuable picks that would help the Seahawks as they try to reshape their roster.

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Thomas' contract is a main part of this equation. He's entering the final year of a four-year, $40 million extension signed in 2014 and has threatened to hold out if he doesn't get an extension. It's presumed that Thomas, who turns 29 in May, wants a deal that either matches or tops that of Kansas City's Eric Berry, the NFL's highest-paid safety at $13 million per year.

There's no question Thomas is every bit as good if not better than Berry. But giving big-money extensions to players approaching or over 30, with injuries starting to mount, is a risky proposition. The Seahawks have two fresh reminders of that with Bennett and Chancellor, and Thomas' next deal could be the most expensive of the three.

Also fresh in Seattle's memory is what happened in 2015, when Chancellor held out all summer and through the team's 0-2 start to the season. Let's say Thomas does indeed demand Berry money, the Seahawks decide that's too high and they feel Thomas would be every bit as obstinate as Chancellor was in 2015 if not more so. The potential for a repeat of that situation would be another reason to trade Thomas, along with the draft picks they'd get in return and money they could instead use elsewhere.

The case against trading Thomas

Let's start with the obvious: Thomas is a rare talent who might be as difficult to replace as any player on the team outside of quarterback Russell Wilson.

The Seahawks already have experienced what life is like without him, and it wasn't pretty. Seattle's pass defense, so good for so long, was certifiably bad while Thomas was sidelined late in the 2016 season. Among many stats that illustrate the drop-off was this: Seattle went from allowing seven passing touchdowns with 10 interceptions and a 77.8 passer rating with Thomas on the field to 12 passing TDs/one interception and a 100.3 passer rating without him.

That offered statistical evidence to support the long-held belief that Thomas is the most important member of Seattle's defense. And his importance figures to grow in the absence of several mainstays like Sherman, Chancellor and Bennett. The Seahawks are going to have a hard enough time replacing those three let alone Thomas.

Yes, recently re-signed Bradley McDougald fared much better as Thomas' replacement for two games last season than Steven Terrell did in 2016. But that was over a shorter stretch, and though McDougald has shown he can play free safety, Chancellor's situation leaves a void at strong safety, where McDougald started seven games last season.

As for Thomas' injuries, it's true he's no longer the player who seemed indestructible earlier in his career when he didn't miss a start for his first six and a half seasons. But even while dealing with an assortment of issues last season, including a hamstring pull that sidelined him for two games, Thomas played at at his typically high level. That suggests he could have a few more prime seasons left.

If the Seahawks are going to part with such an important player, it would have to be for a worthwhile return, perhaps no less than a first-round pick plus another mid-round selection. But remember, any team trading for Thomas would not only have to give up the picks, which would otherwise be spent on young, cost-controlled players. In all likelihood, the new team also would have to give Thomas a massive extension.

That will inevitably narrow the field of interested teams, perhaps to the point that the Seahawks don't get what they deem a suitable offer.