Sure, they're voluntary, but they're also far from pointless.
As of this past week, running back James Cook is the only player who has failed to check in for Buffalo Bills' OTAs in Orchard Park, but as the seemingly-disgruntled holdout works out on his own, Cook's teammates are taking advantage of priceless opportunities at One Bills Drive.
Starting defensive end Greg Rousseau, who, unlike Cook, received a lucrative contract extension this offseason, revealed what the Bills are accomplishing during the three-phase program that kicked off back on April 21.
“I'd say I try to get out of OTAs kind of the same thing I get out of any practice," said Rousseau as Buffalo began Phase 3, which allows for non-contact team drills of the 11-on-11 and 7-on-7 variety.
Rousseau, a 2021 first-round draft pick who tied his career high by making 8.0 sacks this past season, is approaching the springtime team activities with a purpose.
"Whether it's me working on my eyes, my eye progression, my hands, you can pretty much work on everything in OTAs that you can in a normal practice. I mean, we don't have shoulder pads on, so it's not as physical, but when it comes to the technique stuff, you could have a plan and you could execute what you want to execute and just be dialed in on that," said Rousseau.

The 25-year-old edge rusher also highlighted the team-building aspect of OTAs for the five-time defending AFC East champions. It's a chance to become acclimated with new line mates like Joey Bosa, Larry Ogunjobi and rookie TJ Sanders.
“Just by talking to them, honestly. Bosa, Larry, TJ, I talked to them specifically. They all like anime, so there's little things like that, like off the field stuff where you can kind of build that, build that bond and build something to talk about. It carries on to the football field and it shows, it shows a lot in the fall and winter," said Rousseau.
The importance of OTAs can be summed up by the fact that NFL MVP quarterback Josh Allen made it a point to attend practice on Tuesday in Orchard Park despite being only days away from his May 31 wedding.