NFL owners hope to resume in-person offseason workouts this spring, sources tell ESPN's Chris Mortensen, but the NFL Players Association is continuing to advocate for another fully virtual program.

The sides have begun a complex set of negotiations to determine the parameters of offseason work as vaccinations against COVID-19 become widely available. NFLPA president JC Tretter said in December that the virtual 2020 offseason should be made permanent, citing the reduced wear on players' bodies, and the talks are also connected to owners' looming vote on expanding the regular season to 17 games and cutting the preseason to three games.

Owners are expected to approve the 17-game season during virtual meetings next week, a decision the NFLPA maintains would trigger a revision of offseason workout terms in the sides' collective bargaining agreement (CBA).

If owners demand in-person workouts, the sources said, the NFLPA will ask the league to conduct daily COVID-19 testing. Owners believe daily testing will not be necessary by the time training camps open in July because most players will be vaccinated by then. The league spent more than $100 million in 2020 on COVID-19 protocols, with daily testing representing one of the largest line-item expenses.

In 2020, players met with coaches via video conference and followed prescribed training regimens at home or in nearby gyms. The arrangement was deemed by both sides to be suitable in a pandemic, but coaches have long advocated for more, not less, offseason workouts. Tretter, however, said the 2020 season demonstrated that in-person workouts were not needed.

"The argument in favor of these offseason practices is based on the assumption that players need reps during OTAs to develop and learn while teams need the practices to gel," Tretter wrote in a December blog post on the NFLPA web site. "Yet, the lack of OTAs this year demonstrated that those theories aren't substantiated. New and first-year head coaches had success. Newly assembled teams had success. Rookies stepped in and played at a high level all across the league.

"... We do not need to be brought in during April-June to practice against each other -- it's simply unnecessary."