The NFL says reported concussions rose 58 percent in regular-season games to the highest number in any of the past four years.
The league's concussion data for 2015 also showed that helmet-to-helmet hits were way up.
Jeff Miller, the NFL's senior vice president of health and safety policy, said during a conference call the league will study what might have caused the incidence of head injuries to rise so much this season.
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Among the possible explanations mentioned by Miller were a doubling in the number of players screened for possible concussions, ''unprecedented levels of players reporting signs and signals of concussions,'' and the fact that trainers who work as spotters or independent neurologists on sidelines ''are much more actively participating in identifying this injury.''
SAN DIEGO (AP) Chargers Chairman Dean Spanos said the team will play in San Diego in 2016, and he'll work with politicians and the business community to try to resolve a long, bitter fight over a new stadium.
Spanos' statement was posted on the team website shortly after the Union-Tribune reported that the Chargers had agreed in principle to join the Los Angeles Rams in a stadium expected to open in Inglewood in 2019.
It also came shortly after Spanos invited Mayor Kevin Faulconer and County Supervisor Ron Roberts to his La Jolla home for an afternoon meeting.
''I am committed to looking at this with a fresh perspective and new sense of possibility,'' Spanos' statement said.
A spokesman for Faulconer said Mark Fabiani, who has led the Chargers' stadium push for 15 years, was not at the meeting. It wasn't immediately clear if Fabiani, who has attacked Faulconer's proposals for the last year, will be involved when negotiations resume.
GREEN BAY, Wis. (AP) - Packers quarterback Aaron Rodgers says he had knee surgery days after Green Bay was eliminated from the playoffs, according to a report.
Rodgers told ESPN.com that he was ''doing well'' and ''recovering on schedule.''
A Packers spokesman told The Associated Press that he didn't have any injury information.
The Packers lost to Arizona 26-20 in the divisional round on Jan. 16. Rodgers pulled out of the Pro Bowl later that week, citing an unspecified injury.
His 92.7 passer rating was his lowest since taking over as the starter in 2008. Rodgers was on the injury report for one week this season for a sore right shoulder in Week 11.
In college at California, Rodgers had surgery to repair a torn left ACL.
LOS ANGELES (AP) - The Los Angeles Clippers consider their investigation of Blake Griffin's punch-out of a team staff member to be closed, and coach Doc Rivers says Griffin ''feels awful'' for the incident that happened on the team's recent road trip.
The club is awaiting the outcome of the NBA's investigation into the Jan. 23 altercation in Toronto between Griffin and assistant equipment manager Matias Testi that resulted in the star forward breaking his right shooting hand. Griffin wasn't at Friday night's game against the Lakers - he's expected to be out another four-to-six weeks after not playing since Dec. 26 because of a different injury. The Clippers did not indicate whether Griffin will be punished by the team.
Testi wasn't at Staples Center either.
Rivers says Griffin and Testi have since talked, although the coach said he didn't know what was said.
Earlier in the week, Rivers had said alcohol wasn't involved in the incident at a restaurant. However, he says he believes both men had consumed.
Mississippi has been notified by the NCAA of rules violations involving the football, women's basketball and track and field programs.
Some of the allegations regarding the football program date back to previous coach Houston Nutt, but others involve current coach Hugh Freeze's tenure, a person familiar with the investigation told The Associated Press.
The person spoke on condition of anonymity because the investigation is ongoing. The person said the Ole Miss football program has already taken some steps - like reducing recruiting official visits - to try to mitigate any punishment from the NCAA.
Yahoo! Sports first reported that Ole Miss was aware of the Notice of Allegations.
The announcement was not unexpected but comes at a bad time for the football program, which is trying to lock down one of the nation's most highly regarded recruiting classes before national signing day on Wednesday.
SOUTH BEND, Ind. (AP) - Brian Kelly has agreed to a six-year contract to stay on as coach at Notre Dame through the 2021 season.
The deal announced by athletic director Jack Swarbrick would make the 54-year-old Kelly, who has been at the school six seasons, the second-longest serving Irish coach in history. Knute Rockne coached 13 seasons from 1918-1930 before he died in a plane crash in Kansas at age 43.
Frank Leahy, Ara Parseghian and Lou Holtz all coached the Irish 11 seasons.
Swarbrick, who hired Kelly after firing Charlie Weis following the 2009 season, said he is excited about the future of the program under Kelly.
Terms of the contract were not disclosed. The announcement comes five days before signing day, with Kelly on the road recruiting.
LOS ANGELES (AP) - Driving to Dodger Stadium? From now on, take Vin Scully Avenue.
A road leading to the ballpark is being renamed in honor of the famed announcer, who is set to begin his 67th season with the Dodgers.
The Los Angeles City Council voted unanimously to change the name of Elysian Park Avenue in tribute to the 88-year-old broadcaster. New Dodgers manager Dave Roberts, star pitcher Clayton Kershaw and several other players were on hand in the council chambers for the vote.
Scully said in a statement that he was greatly honored by the gesture. He added: ''A path to Dodger Stadium is a pathway to my heart.''
Scully has said this is likely his last season behind the microphone for the Dodgers. He started his career with them when the team was based in Brooklyn.