The Dolphins announced the suspension Thursday. In a statement released by the team, Jordan took "full responsibility" for the positive test.
"I recently learned from the NFL that I tested positive for stimulants that are banned under the NFL policy," Jordan's statement read. "I worked carefully with my advisors and the union to investigate the test results, and I take full responsibility for the test results."
Jordan's statement also included an apology for the "impact of this situation" on his teammates, coaches, Dolphins owner Stephen Ross, his fans and family.
"We were disappointed to learn about Dion's suspension," Dolphins coach Joe Philbin said through the team. "Dion has accepted responsibility for his actions and is committed to improving, both on and off the field, in preparation for the upcoming year."
Jordan was the third overall pick in the 2013 draft out of Oregon. He says he added more than 15 pounds of bulk this offseason in an effort to improve his game, earning praise from Philbin for being able to play faster as well.
"I would never sacrifice my speed for weight," Jordan said last month.
He played in all 16 games with Miami a year ago, with 26 tackles and two sacks.
Jordan will be able to participate in training camp and preseason games. Once the regular season starts he will not be permitted to be part of the Dolphins' active roster until Sept. 29, according to an NFL spokesman.
Jordan will miss games against AFC East rivals New England and Buffalo, as well as matchups with Kansas City and Oakland. The first game he would be eligible for would be Oct. 12 against Green Bay, a game that follows the Dolphins' bye week.
"I will continue to work extremely hard during training camp and preseason," Jordan said. "During the suspension, I will stay in top shape and will be ready to contribute upon my return."