NFL commissioner Roger Goodell called the 2014 NFL season a year of “real progress” in his annual State of the League address and focused his speech on ways to improve the game while making the league safer.

Goodell said the NFL will focus on three aspects over the next year - the game, player safety and fan experience.

Speaking on how to improve the game, Goodell said the NFL plans to advance ideas to challenge kickers on the extra point this season. The commissioner also noted the league continues to consider expanded playoff formats.

On player health and safety, Goodell said he was pleased with the league’s progress after concussions dropped 25 per cent from 2014 to 2013, but admitted there remains work to be done. He also announced the league's plan to hire an executive who will work with the league's medical committees, advisers and the NFL Players Association.

Goodell noted additional technology could help fan experience and focused on quicker review times and more consistent refereeing, even considering using reviews for penalties.

Speaking of ‘deflate-gate’ involving the New England Patriots, Goodell said the league was focusing on why under-inflated footballs were used and whether or not the footballs were intentionally deflated. Goodell said no judgment has been reached yet on the case. As to Patriots owner Robert Kraft's demand of an apology for the investigation, Goodell said his responsibility to league and fans is to "protect integrity of the game" and "make sure rules are being followed."

Goodell added the NFL won't decide on any discipline for Seahawks running back Marshawn Lynch until after the Super Bowl. Lynch has kept all his media appearances this week to five minutes or less and hasn't said much. He has also donned hats with logos of his own apparel line, which are not sponsored by the NFL.

While Goodell did not comment about what the possible penalty might be, he made clear that Lynch had an obligation to do the interviews.

"It's part of your job," Goodell said. "There are things in your job that you might not necessarily want to do. I think Marshawn understands the importance of the Super Bowl and the importance of his appearance in the Super Bowl."

On relocation to Los Angeles, Goodell said the NFL hasn't yet zoned in on a specific team for a possible move to the city and any move will be subject to the league's relocation policy.

The Rams, Chargers and Raiders are candidates to move to the country's second-largest city, which has been without a team since the 1994 season.

A company with ties to Rams owner Stan Kroenke has purchased a site 10 miles from downtown Los Angeles, though no development plans have been announced.

At his news conference Friday, Goodell said the league's main priority is keeping teams where they are.

"We know there are teams interested (in moving) but they're trying to work their issues out," Goodell said.

Goodell did not make any commitment to possibly placing a full-time team overseas but did say the NFL would continue to "respond to that fan interest, and if we do, we don't know where it'll go, but there's great potential for the NFL in London."