Owners are cautious, and players are furious.

Spring training camps opened throughout Arizona and Florida, yet the usual sounds of baseballs popping into gloves are being drowned out by the noise of players popping off about their unsigned brethren on the free-agent market.

When Buster Posey makes pointed comments about teams failing to competitively build rosters, people take notice. Justin Verlander, Christian Yelich, Clayton Kershaw and others joined the fight to suggest the system is broken and needs fixing.

The collective bargaining agreement ends in December 2021, yet friction is escalating between the sides with Bryce Harper, Manny Machado and dozens of other free agents still without teams, the second straight sluggish market.

The more the bad blood elevates and the more revenues increase and payrolls decrease, the more we’ll hear about the possibility of baseball’s first work stoppage since the 1994 and ’95 seasons.

“A strike is the last thing you want to do, but you have to be willing to do it,” said Giants pitcher Jeff Samardzija, who benefited from free agency at a time teams were more willing to build rosters with accomplished players. “There are other things we can do before then to get the ball going in the right way.”

Giants third baseman Evan Longoria, who signed long term with the Rays before he was eligible for free agency, is another high-paid player expressing distrust with owners, though he made a point to exclude the Giants, who had a top-three payroll last year.

“As players,” Longoria said, “the fear is there are other organizations that don’t care about putting the best product on the field, that are essentially tanking, that don’t want to sign players because they either want a better draft pick or are just going to go out and pay somebody less money than picking somebody from the free-agent pool.

“That’s the message for me. It’s not about me. It’s for players like Steven Duggar and our younger players and younger generation who are looking a few years down the line at free agency or arbitration.”

In simple terms, teams paid players in the past for what they had accomplished, and now they’re paying for projections, which can be more of a crapshoot but far cheaper. At the same time, players are under team control for six seasons, with many reaching career peaks while their earning potential is lowest.

The first three years, players hover around the big-league minimum, and the next three years they’re eligible for arbitration. Free agency doesn’t hit until the seventh year when players often are on the wrong side of 30.

It has become easy for teams to pass on those players in favor of less-expensive alternatives with less service time. This hits home with the union and its pursuit to reconstruct the labor agreement.

“We’re going to have to get the arbitration moved up a year earlier. We’re going to have to get guys to free agency earlier, and it seems there might be only one way to get that,” said Samardzija, hinting of a strike.

“We’ll see. We hope it doesn’t come to that. We want to keep the fans happy. We want people coming to the stadium and watching a great product. But they need the best product available, and having 50 guys sitting at home who are big-league players is not the best product.”

Samardzija has ideas on how to resolve the issue: punishing teams that aren’t attempting to be competitive.

“I think it has to be performance-based,” he said. “I think you regulate bad performance by taking away slot money and draft picks. Clearly, it’s pretty simple. They’re valuing pre-arb guys over free agents. Even if there’s a little tick off of production.

“There has to be a way to get teams better today, right now. And for that, you have to take away something from them in the future. If you’re a bottom-four team in the league, you get docked X amount of international slot bonus money, draft money or draft picks.

“You’ve got to hit these guys the only place it hurts, in their wallet. How you hurt them in the wallet, you have to make sure they ain’t getting work for cheap. And right now, they’re getting four years, essentially, of cheap work out of these guys before they just trade them anyway for more younger prospects.”

Giants CEO Larry Baer, noting the five-year CBA is nearing its midpoint, said he expects the issues to be addressed.

“Our hope is — and this is being discussed between the players’ association and the owners — we’ll get to productive proposals that address a market that works,” Baer said. “If this is a market that doesn’t work, then we’ve got to change the system in order to make it work better. That’s what we all want. I think it’s going to happen in the context of labor negotiations.”

Players aren’t so sure. It’s a sore spot that teams are treating the luxury tax threshold as a salary cap and haven’t lined up to bid for Harper and Machado — or even the middle-class free agents — when several teams, including in major markets, suggested last year they were staying beneath the threshold to put themselves in prime position to pursue these free agents.

“There’s enough money out there. I don’t think any of these owners are going to sleep hungry,” Samardzija said. “You just hope for a little more competitiveness out of the owners, the same competitiveness that we see out of each one of these players, who are trying to beat each other on the other team but also trying to take each other’s jobs on the same team. We live and die by that. You just hope you’re getting the same back from up top.”

John Shea is The San Francisco Chronicle’s national baseball writer. Email: jshea@sfchronicle.com Twitter: @JohnSheaHey