Last July, Major League Baseball issued a memo to every player on all 30 clubs as a direct response to the conspiracy theories circulating about the most crucial component of its product: the baseball itself.

Countering rumblings that the league’s baseballs were “juiced” to generate more scoring, MLB insisted its meticulous examination of game balls remained unchanged and the results categorically demonstrated the balls weren’t any different. While position players shrugged their shoulders, pitchers weren’t buying it. They wanted more proof nothing had changed. And nearly nine months later, as the 2018 season is set to open Thursday, skepticism remains.

“I have questions. I have questions,” Washington Nationals closer Sean Doolittle said recently. “I think so much of this could’ve been put to rest [last July]. They basically said, ‘We did a study. The balls are the same.’ And then they didn’t hold a press conference on it. They didn’t make the study available. It almost led to more questions and it didn’t entirely pass the smell test. As players, I think if we just had the answers we would be able to move on and we [could] put it all to bed.

Last season’s all-time-high home run rate – far outpacing even the Steroid Era – sparked speculation that the surge went beyond pitchers throwing harder and some batters preaching the launch-angle gospel. The unprecedented offensive numbers in 2017 indicate something, whatever it was, changed. There were 6,105 home runs last season, smashing the previous record of 5,639 homers set in 2000, when performance-enhancing drug use was rampant. The output extended a three-season uptick – and doesn’t include the World Series home run record the Houston Astros and Los Angeles Dodgers needed just five games to establish.

An ESPN “Sport Science” study argued the difference was in the density and chemical composition of the balls’ cores. A change, the study suggested, occurred after the 2015 MLB All-Star Game. Earlier this month, the website FiveThirtyEight published its own study, which concluded chemical changes to the core, an increase in bounciness and a decrease in air resistance combined to let balls travel up to 8.6 feet farther than balls before the 2015 All-Star Game. The distance, the site concluded, generated a 25 percent increase in home runs.

Major League Baseball, however, has maintained nothing was altered. Last month, Commissioner Rob Manfred said the league conducted a postseason-long project with “independent experts” that wasn’t yet finished, but that MLB will release results and recommendations for the future once the study is complete. He offered a hint of the findings on Feb. 15 at the Grapefruit League Media Day in St. Petersburg, Florida.

“I know, even with the additional research,” Manfred said, “that all of the findings on the basic variables that we’ve always kept track of indicate that the baseballs are the same.”

Doolittle, who began last season with the Oakland Athletics, said he immediately noticed that the balls seemed unusual. The stitching felt inconsistent. Sometimes the seams were low, other times they were high. He said he didn’t recall sensing differences that drastic in previous seasons. Fellow reliever Ryan Madson, who accompanied Doolittle in the trade from Oakland to Washington, recalled thinking the same.

The suspicions echoed in the Nationals clubhouse, which Doolittle and Madson joined a couple of weeks after the memo’s release. On the day the memo was delivered, one Nationals pitcher remarked how there were home runs he allowed up to that point in the season that he was positive would have stayed in the park in the past.

“When we’re talking about 190-pound guys hitting it one-handed off the wall,” another National said, “it kind of makes you scratch your head a bit.”

Earlier this month, Houston Astros hurler Justin Verlander brought that skepticism back to the forefront with a pair of tweets. In the first, the 2011 AL MVP shared three graphs displaying the increase in home runs from 2014 and 2017 on contact with identical launch angle and exit velocity. He followed it up by tweeting he didn’t care if the “balls are juiced” and he just wanted the truth, which he adamantly concluded hasn’t been disclosed. Nationals ace Max Scherzer echoed his former Detroit Tigers teammate’s call for transparency.

“If there are changes with the ball, we would like to know if that is a factor or not,” said Scherzer, the two-time defending NL Cy Young Award winner. “You’re only human. No one’s going to sit here and tell you, ‘Yeah, you can do whatever you want to the ball without telling us.’ That’s the only thing that I think gets everybody in a hissy fit.”

Some pitchers, of course, proved better equipped to counter the surge in long balls, however it was manufactured. Two of them, Scherzer and Stephen Strasburg, happen to top Washington’s starting rotation. Both front-line starters had their home run rates diminish from 2016 to 2017 and both maintained complaining about the balls does no good. Every pitcher has to deal with the same balls. Execution trumps all. But uncertainty remains, and clarity is preferred.

“It’s hard to know what to believe,” Strasburg said.