This is the second suspension in two seasons for Boyle, who was banned for the final four games last season for the same violation.
Boyle's suspension increases the chances of the Ravens drafting a blocking tight end in the later rounds of the NFL draft in late April. Baltimore returns its two top tight ends in Crockett Gillmore and Maxx Williams.
Boyle, a fifth-round pick in 2015, was one of the Ravens' most productive rookies last season before the suspension. He caught 18 passes in 11 games and proved to be a solid blocker.
After his first suspension in December, Ravens coach John Harbaugh would not disclose the substance that led to Boyle's discipline, but said, "It's pretty common, [a drug] you read about all the time with guys. ... It wasn't steroids or anything like that."
Harbaugh added, "I don't think he realized it's something he shouldn't be doing, or if he did, he just didn't think it through. He told me how stupid it was. I agree. It was pretty dumb."
Boyle tweeted an apology after the first suspension.
I am truly sorry for the disappointment I have caused by a poor choice I made. I am ready to move forward and I appreciate all the support.
— Nick Boyle (@nickboyle86) December 11, 2015
Boyle is eligible to participate in all offseason and preseason practices and games. His suspensions will cost him a total of $387,092, or 45 percent of his salary for his first two seasons in the NFL.