Lewis will be eligible to return to the Lions' active roster on Monday, Dec. 30 following the final regular season game Dec. 29 at Minnesota.
"All NFL players know they are responsible for their actions, and they also know there are consequences when their actions are not consistent with league policy," Lions general manager Martin Mayhew said in a statement released by the team shortly after the announcement.
"While we are disappointed that Travis violated league policy and will miss the next four games, we expect that Travis will learn from this experience and not repeat it."
Lewis has played in all 12 games this year on special teams and has six tackles. He was a seventh-round pick in last year's draft.
"I apologize to my coaches, teammates, the Lions organization and our fans for my actions," Lewis said in a statement.
"I have let my team down and there's nothing worse than that.
"I will not make the same mistake again. I look forward to returning to the team after I serve my suspension."
Lewis will be placed on the Reserve/Suspended list and the Lions signed linebacker Julian Stanford to take his place on the roster.
Stanford, 6-1, 230, is in his second season out of Wagner.
He played in all 16 games with the Jacksonville Jaguars last season with six starts. He recorded 23 tackles.
He was released by Jacksonville during final cuts in training camp.