In a pair of tweets posted Tuesday, James urged Manfred to listen to players from around Major League Baseball and "fix this for the sake of sports."
"Listen I know I don't play baseball but I am in sports and I know if someone cheated me out of winning the title and I found out about it I would be [expletive] irate!" James wrote on Twitter. "I mean like uncontrollable about what I would/could do! Listen here baseball commissioner listen to your players speaking today about how disgusted, mad, hurt, broken, etc. etc. about this.
"Literally the ball is in your court[or should I say field] and you need to fix this for the sake of sports!"
James joined a growing list of athletes who have called out Manfred and the Astros in recent days.
Los Angeles Dodgers stars Cody Bellinger and Justin Turner, whose Dodgers lost the 2017 World Series to the Astros in seven games, voiced their displeasure with the punishment handed down on the Astros organization. Los Angeles Angels star Mike Trout and New York Yankees slugger Aaron Judge also took aim at Manfred's handling of the case.
Major League Baseball announced last month that a league investigation confirmed the Astros cheated during the regular season and postseason of their World Series-winning 2017 campaign.
According to Manfred, the Astros used a camera-based system to steal signs of opposing teams during the 2017 season and parts of the 2018 campaign.
The sign-stealing scandal led to the suspension and subsequent firing of former Astros manager A.J. Hinch and general manager Jeff Luhnow last month. The Astros organization was also fined a record $5 million and had multiple draft picks taken away.
But none of the Astros players involved with the operation were suspended or fined, and Manfred previously indicated that MLB had no plans to strip the Astros of their 2017 World Series championship. Those decisions have drawn widespread criticism from players and managers from around the league, including athletes outside of baseball.
Manfred has defended his punishment of the Astros this week, but came under fire for his characterization of the World Series trophy. The baseball executive called the Commissioner's Trophy a "piece of metal" during a wide-ranging interview with ESPN.
Manfred later apologized for referring to the trophy "in a disrespectful way."
"I've awarded five World Series trophies," Manfred said Tuesday. "There is no greater pleasure in this job than awarding that trophy. I understand what it means. And again, it was a mistake to say what I said."