Dyson, who hasn't pitched in the majors since 2019, will participate in an evaluation and treatment program.
"Having reviewed all of the available evidence, I have concluded that Mr. Dyson violated our policy and that discipline is appropriate," commissioner Rob Manfred said.
MLB reportedly launched an investigation in November 2019 after social media posts by Alexis Blackburn, Dyson's ex-girlfriend, implied he committed animal abuse toward their cat and alluded to abusive behavior against her.
"This has been the hardest battle I have ever faced," Blackburn said, according to Katie Strang of The Athletic. "I felt like I had to prove myself to the world. ... (my cat) Snuckles and I are finally happy, living our best lives. This is just the beginning of our new life.
"We fought hard and we were validated by one of the largest sports organizations in the world. I'm finally proud of the woman I am and no one can take that away from me. This is a win for victims and survivors across the world."