Mota, 33, will begin serving the suspension effective at the beginning of the 2007 season. The right-hander is currently a free agent, having filed on Monday.
"I have no one to blame but myself," Mota said in a statement released to the Associated Press. "I take full responsibility for my actions and accept MLB's suspension. I used extremely poor judgment and deserve to be held accountable.
"To my teammates and the entire Mets organization, I am sorry. I truly regret what I did and hope that you can forgive me. To baseball fans everywhere, I understand that you are disappointed in me, and I don't blame you. I feel terrible and I promise this is the first and last time that this will happen. I am determined to prove to you that this was one mistake."
Mota was acquired by the Mets from the Cleveland Indians on Aug. 21 for a player to be named later. He appeared in 18 regular season games for New York, plus seven more in the postseason.
After going 1-3 with a 6.21 ERA in 34 appearances for Cleveland, Mota came to New York and had exceptional results, going 3-0 with a 1.00 ERA and striking out 19 in 18.0 innings down the stretch to earn manager Willie Randolph's confidence.
Mota was the winning pitcher in Game 1 of the NL Division Series against the Los Angeles Dodgers, but surrendered a two-run triple to Scott Spiezio of the St. Louis Cardinals in Game 2 of the NL Championship Series for a blown save.
After that game, it was revealed Mota shook off catcher Paul Lo Duca's call for a change-up, instead throwing a fastball that Spiezio drove just out of the reach of right fielder Shawn Green.
After the Mets were eliminated in the NLCS, Mota said that he was hoping to return to the Mets, though the suspension could severely alter his chances.
He has a career record of 26-27 with a 3.70 ERA in 438 major league appearances with the Dodgers, Florida Marlins, Indians and Mets.