The Boston Red Sox are drawing new attention to Major League Baseball's ongoing controversy surrounding the condition of its baseballs.

Several Red Sox pitchers - all of whom requested anonymity - told Rob Bradford of WEEI on Tuesday that they've noticed an increase in warped baseballs this season. They described these balls as being deformed in shape or even flat, sometimes after being put in play by hitters.

"Opening Day in Tampa we got a ball back into the dugout and it was almost flat on one side," one Boston pitcher told Bradford. "I've never seen anything like it."

"It's frustrating," added another pitcher. "I don't really have a plan for throwing a baseball that's not round."

MLB has seen home-run rates skyrocket over the past several seasons, leading to speculation that a root cause of the spike may be from changes to the baseballs. An expert study commissioned by the league last month did find a change in the balls' aerodynamic properties, but ruled out physical changes to the balls as being behind the increase.

Related: MLB study confirms baseballs getting extra lift since 2015, but cause unknown

Speaking specifically to the Red Sox pitchers' complaints, an MLB spokesperson told Bradford that the league was unaware of any issues regarding warped or misshapen balls, before adding that "we will track it in line with our protocols."

Copyright © 2018 Score Media Ventures Inc. All rights reserved. Certain content reproduced under license.