On October 7th, a person going by the name of Emily Smith on Twitter posted that Cole had groomed and had a sexual relationship with her while she was a minor in high school and he was in the NHL.
Cole denied the allegations, but the NHL suspended him with pay while an investigation was conducted.
"I'm grateful for the opportunity to respond to and refute the anonymous allegations made against me, which I categorically deny," Cole said in a statement.
"I'm looking forward to returning to the ice with my teammates and will have no further comments on this matter going forward."
The NHL security and legal departments said they interviewed Cole twice and also spoke to club personnel, individuals with potentially relevant information and reviewed online data as well as court and law enforcement records.
The NHL said investigators were unable to make contact with the anonymous source of the social media post.
"The National Hockey League now considers this matter closed," it said.
The NHL Players' Association said it was worried about the precedent set by suspending Cole over the allegations.
"Players should never be subject to suspension or discipline in response to unsubstantiated and anonymous accusations," the NHLPA said in a statement.
"Removing a player from his team under these circumstances is inappropriate and grossly unfair. We are engaging the League in discussions on how to address similar situations in the future."
Cole, 33, has won the Stanley Cup twice as a member of the Pittsburgh Penguins, in 2016 and 2017, and signed with the Lightning as a free agent over the summer.
The Ann Arbor, Michigan native attended the University of Notre Dame and was selected 18th overall in the 2007 NHL Entry Draft.
