Kansas City Chiefs' NFL free-agent signings 2021: Joe Thuney, Kyle Long begin OL rebuild

NFL free agency is off and running, and we're keeping track of every major signing, trade and release of the 2021 offseason, with analysis from our NFL Nation reporters and grades from our experts. The new league year began March 17 at 4 p.m. ET, meaning free-agent signings can be made official after that. The first round of the 2021 NFL draft begins April 29 on ESPN.

The Chiefs are attempting in 2021 to become just the fourth franchise to appear in three straight Super Bowls. They couldn't repeat as NFL champions last season, losing in Super Bowl LV to the Tampa Bay Buccaneers 31-9.

They'll bring back a solid group of returning players, led by quarterback Patrick Mahomes, tight end Travis Kelce and wide receiver Tyreek Hill. But the loss to the Bucs revealed more than a few flaws, the biggest being that the Chiefs need to pay more attention in free agency and the draft than they have to the offensive line, which was overwhelmed in the Super Bowl by the Bucs' defensive front.

Here's a breakdown of every 2021 NFL free-agent signing by the Kansas City Chiefs, and how each will impact the upcoming season:

Joe Thuney, guard

The Chiefs and free-agent offensive lineman Joe Thuney have agreed to a five-year, $80 million deal.

What it means: The Chiefs are serious about rebuilding their offensive line. Days after releasing two of their better lineman in tackles Mitchell Schwartz and Eric Fisher, the Chiefs are sinking big money into perhaps the best guard on the free-agent agent market. Assuming Laurent Duvernay-Tardif returns after opting out of last season, the Chiefs should be set at guard. The Chiefs could have an entirely new starting offensive line in 2021 from last year's season opener.

What's the risk: There's always a risk in signing big-money free agents. The Chiefs might not get an adequate return on their investment. In this case, though, there was more risk for the Chiefs with inaction. The Chiefs were dominated up front in the Super Bowl loss to the Tampa Bay Buccaneers and couldn't risk that happening again. Finding better protection for quarterback Patrick Mahomes was job No. 1 during this offseason, and this signing is a great start.

Kyle Long, guard

Kyle Long came out of retirement and signed a one-year deal with the Chiefs.

What it means: The rebuild of the Chiefs' offensive line continues. If Long, who sat out last season in retirement, returns as anything close to the player he was for the Bears earlier in his career, the Chiefs will be getting a bargain. Long played at tackle for one season early in his career and he may have to play that spot for the Chiefs, who recently signed Joe Thuney and have Laurent Duvernay-Tardif returning after opting out last season.

What's the risk: Long sat out last season in retirement. Before that, because of injuries, he hasn't played a full season since 2015. So if Long plays well and for a full season in 2021, they should consider that a bonus. But it's a mistake for them to count on that. If he gets a starting spot next season, the Chiefs need to have a backup plan in place.

Austin Blythe, center

The Chiefs have agreed to a one-year deal with former Los Angeles Rams center Austin Blythe.

What it means: The Chiefs have a starting center to replace Austin Reiter, their regular for each of the past two seasons. Blythe started in each of the last three seasons for the Rams, so the Chiefs are getting an experienced player. The signing is just for one season and doesn't eliminate the possibility the Chiefs could select a center in the upcoming draft. But it's no longer a necessity.

What's the risk: The Chiefs appear headed toward having five different offensive line starters from last year's season opener. That isn't a bad thing, particularly given how the line was dominated by the Bucs in Super Bowl LV. But it might take some time for the Chiefs to fit everything together.

Jarran Reed, defensive tackle

Jarran Reed agrees to a one-year deal with the Chiefs.

What it means: Reed, who has 19 sacks in the past three years, could team with defensive tackle Chris Jones to give the Chiefs a strong interior pass-rushing combination. Reed will join a playing rotation that includes Jones, Derrick Nnadi and Tershawn Wharton. Nnadi is mostly a run defender. Wharton showed promise last year as an undrafted rookie but isn't as accomplished as Reed.

What's the risk: Reed is on a one-year deal so if he doesn't play well the Chiefs aren't stuck with an unproductive player and a burdensome contract for the long term. The Chiefs also have options in Nnadi and Wharton but they'll have a stronger front if Reed stays healthy and is productive.

Demarcus Robinson, wide receiver

Career highs in catches and yards in 2020 couldn't earn a multi-year contract for free agent wide receiver Demarcus Robinson, who instead re-signed with the Chiefs for one year.

What it means: Robinson provides some much-needed depth at a position that -- with Sammy Watkins a free agent -- is thin behind Tyreek Hill. It's hard to envision Robinson starting the season as a regular given that the Chiefs looked elsewhere in free agency for a replacement for Watkins before re-signing Robinson. But he knows the offensive system well so his return is welcome news for the Chiefs.

What's the risk: Robinson, who is heading into his sixth NFL season, has probably reached his potential. He's not going to be the No. 2 wide receiver the Chiefs need. But that's not the role they signed him for. He's more than adequate with the other receivers they have as a down-the line option.

Daniel Sorensen, safety

Daniel Sorensen is returning to the Chiefs on a one-year deal.

What it means: Sorensen played more snaps than any Chiefs defensive player last season other than Tyrann Mathieu so it's no surprise the sides were able to come to an agreement on a new one-year contract. Sorensen may have something less than a regular role on defense this season as fellow safety Juan Thornhill will be almost two years removed from his torn ACL. But the Chiefs have a comfort level with Sorensen so he could well find some playing time.

What's the risk: Not much. The Chiefs are familiar with Sorensen's game. He will give the Chiefs the same play he has since he first started playing for them in 2015.

Taco Charlton, defensive end

The Chiefs are bringing back Charlton on a one-year deal.

What it means: Charlton was mainly a situational pass-rusher last season, his first with the Chiefs, before it ended for him seven games in because of a leg injury. Look for the Chiefs to use Charlton in a similar role this year. He could pair with Frank Clark as the Chiefs' edge rushers on passing downs. Charlton had two sacks and was in general a reliable source of pressure.

What's the risk: Charlton is a situational player. While he brings upside as a pass-rusher, he doesn't hold up well against the run so the Chiefs need to be careful how they use Charlton. The Chiefs are willing to live with this if he rushes the quarterback as effectively as he did last season.

Blake Bell, tight end

What it means: Bell is a journeyman, but during his one season in Kansas City in 2019 he was the most reliable backup to Travis Kelce the Chiefs have had in years. He won't give the Chiefs big numbers but will still be an upgrade over the reserves the Chiefs had last season.

What's the risk: Not much. The Chiefs know what they are getting with Bell.

Mike Remmers, offensive tackle

What it means: Remmers, who had a solid season for the Chiefs last year, could wind up being the starting right tackle. If not, he provides a nice option for the Chiefs off the bench at either tackle or guard. Remmers started at least one game last season at three positions, including the Super Bowl at left tackle.

What's the risk: It wouldn't hurt the Chiefs to have a better backup plan at left tackle than Remmers. Though he handled his other positions well during the season last year, he didn't play well at left tackle in the Super Bowl.

Michael Burton, fullback

What it means: The Chiefs don't use a fullback much, so Burton won't play much on offense. But he's a versatile player who has been a nice fit into West Coast offensive systems at previous NFL stops, so the Chiefs should be getting a capable replacement for longtime fullback Anthony Sherman, who recently retired. Burton's greatest contributions should come on special teams.

What's the risk: Burton is a veteran now with his fifth NFL team, so he knows what it takes to fit in with a new group of teammates and coaches. Still, the Chiefs had a comfort level for several years with Sherman and now are transitioning to someone new.