DeAndre Hopkins has agreed to a five-year extension with the Houston Texans worth $81 million. The deal includes $49 million in guaranteed money, which the largest single guarantee for any wide receiver in NFL history.

Hopkins was a Pro Bowler and Second-team All-Pro in 2015. Hopkins caught 111 balls for 1,521 yards and 11 touchdowns in 2015. Last season, Hopkins caught 78 balls for 954 yards and four touchdowns.

Hopkins held out for a new contract last year.

Last year, the NFL announced a $100 million commitment to concussion research. But in the time since that pledge was announced, the NFL has only funded a study focused on jockeys.

The study aims to find out why high concussion rates in horse racing don't translate into "deteriorating brain function in later life," a question that many scientists believe has little to do with football. The study is led by an Australian researcher who once described American coverage of CTE as "carry-on and hoo-hah" and a British doctor whose concussion presentations sometimes have included flippant jokes and video of tumbling jockeys set to slapstick music. 

The NFL has taken the science in-house and under its control.

"I would view it just as if any giant corporation was doing internal research," said Stefan Duma, a concussion researcher who is the interim director for Virginia Tech's Institute for Critical Technology and Applied Science. "This is internal research that the NFL controls."

Several concussion experts reached by Outside the Lines doubted that equestrian sports were an appropriate vehicle to draw conclusions about long-term mental illness in football players. 

The NFL has announced just two projects from its $100 million "Play Smart, Play Safe" campaign, totaling $210,000.

"It's going to take 500 years to distribute this money" at this rate, said one concussion researcher.

The NFL believes better helmets will improve player safety, though they had a similar initiative in 1994.

"The majority of that $100 million -- $60 million -- is going to technology, and 'technology' is a nice word to say 'better helmet,'" said Dr. Robert Cantu. "They're hoping they can come up with a better helmet that will largely make the problem go away. Helmets can obviously make it better, but no, realistically, it's the violent shaking of the brain, the rapid movement of the head. And the masses involved of individuals colliding with their heads and other body parts is just too great. They could probably get it better, but I don't think the helmet will ever solve the issue."

The Pittsburgh Steelers have signed Kevin Colbert to a two-year extension through at least the 2020 NFL Draft.

Colbert become general manager of the Steelers in 2010 after previously serving for a decade as Director of Football Operations.

“I am excited to announce we have extended Kevin Colbert’s contract for an additional two years,” said Steelers President Art Rooney II. “Kevin’s dedication and diligent work have played a major role in our success. We are pleased he will continue to lead our personnel efforts for at least the next three years.” 

The San Francisco 49ers fired their head coach for the third consecutive season, parting with Chip Kelly after they posted a 2-14 record in 2016. The 49ers also fired general manager Trent Baalke, who previously won an internal battle against Jim Harbaugh.

The 49ers hired Kyle Shanahan as head coach and John Lynch as general manager on six-year deals for approximately $11 million combined per season.

Lynch had no prior front office experience as he was hired away from his television job with FOX.

Shanahan has been a successful offensive coordinator in several stops, though this is his first head coaching job.

The NFL is investigating an alleged domestic incident involving Jarvis Landry, according to a report.

A league spokesman told Andy Slater of WINZ that "the matter remains under review."

The league is believed to be in possession of a video of the incident.

Landry says he's fully cooperated with the investigation and his girlfriend, the alleged victim in the incident, has been uncooperative with authorities and refuted the claims against him.

NFL players have been unable to secure a contract tied to the growth of the salary cap. Darrelle Revis attempted to get it into his contract in 2010 while Kirk Cousins sought a clause in his 2016 negotiations.

The NFL salary cap has grown by 37 percent since 2013.

Teams have resisted tying salary to the cap as it negates their benefit of a long-term deal.

In the NBA, maximum contracts are tied to the salary cap for the first season of the deal and then have pre-determined raises every year thereafter. When a player becomes a free agent again, they can sign for a percentage of the salary cap again depending on their years of service.

As Peter King points out, quarterbacks are making approximately the same percentage of the cap (15 percent) as they were in 1997. Brett Favre had an average salary of $6.5 million in 1997, which was 15.7 percent of the cap. In 2017, Matthew Stafford's average salary of $25.3 million represents 15.1 percent of the cap.

The Seattle Seahawks are looking to trade Jermaine Kearse, according to a report.

Kearse has started at receiver for the Seahawks since 2014, but is coming off a season in which he caught 41 passes for 510 yards and one touchdown.

He is set to make $2.2 million in base salary in 2017 as part of the three-year, $13.5 million deal he signed in March 2016.

The NFL has reduced Vontaze Burfict's suspension from five to three games.

Burfict's suspension was for an illegal hit against Kansas City Chiefs fullback Anthony Sherman during a preseason game.

According to the league, Burfict hit the player while in a defenseless posture. It is a new rule the NFL is implementing this season to protect the player who can't protect himself.

The Kansas City Chiefs have acquired Cam Erving from the Cleveland Browns for a fifth round pick in 2018.

Erving was a first round pick on the offensive line in 2015.

From 2007 through 2016 the Browns took 13 players in the first round of the draft. Three are still with the team.

The Chiefs are set in their starting lineup at both tackle positions, right guard and center for the foreseeable future, with all four players being signed at least through 2018. The only opening for Erving in the starting lineup would possibly be at left guard; last year's starter, Parker Ehinger, has yet to play in the preseason after tearing his ACL last year.

Joe Haden has agreed upon a three-year, $27 million deal with the Pittsburgh Steelers. Haden will receive $7 million in Year 1 guaranteed.

Haden had better financial offers from other teams.

Haden was released on Wednesday by the Cleveland Browns.

Haden last made a Pro Bowl in 2014.