REGINA — The Saskatchewan Roughriders have signed controversial defensive lineman Khalif Mitchell to their practice roster, drawing criticism from Canadian Jewish organizations.

Mitchell hasn't played since being released by the Montreal Alouettes in June 2015, a month after he was fined for violating the CFL's social media policy with anti-Semitic posts on Twitter, which included a link to a Holocaust denial video.

At the time, he apologized in a joint statement by the CFL Players' Association and B'nai Brith Canada, saying it was "a learning moment for me."

"I wholeheartedly apologize to all those who I know I let down by posting those videos, especially those who look up to me as a professional athlete,'' Mitchell said in May 2015. "I fell into a trap by watching that video and I hope others can learn from my very public mistake."

Mitchell agreed to work with B'nai Brith, a Jewish human rights organization, to "educate myself about this and other human rights matters.''

Shimon Koffler Fogel, CEO of the Centre for Israel and Jewish Affairs, said Wednesday there is no evidence Mitchell has learned from his mistakes.

"We are deeply troubled that Mitchell is continuing to spread messages of hate against the Jewish people," he said in a statement. "The Montreal Alouettes and the Canadian Football League did the right thing in 2015 by denouncing Mitchell's hateful tweets and levying a fine against him for his troubling behaviour.

"Clearly, Mitchell has not learned from his past mistakes. We have engaged with the CFL and the Saskatchewan Roughriders and they have assured us they are investigating."

The CIJA included screenshots of several recent retweets from Mitchell that it deemed troubling.

The CEO of B'nai Brith, Michael Mostyn, told Yahoo Sports on Wednesday that he expected the Roughriders to ensure that Mitchell will not use the CFL platform to promote offensive messages.

Roughriders coach Chris Jones said he doesn't go online and hadn't seen Mitchell's recent Twitter activity.

"We've spoken on it," said Jones. "He's a couple years older. I'm hoping Khalif knows where he's at in his life."

Mitchell says he is aware of the reputation he brings to Saskatchewan, but he's comfortable in his own skin.

"I've been around pretty much all the good and the bad at the maximum extremes," he said. "What's going on here is that I got the opportunity to go ahead and show everybody who I am. If you don't know me, all you've got to do is go and look me up and then all of a sudden you'll find out who I am.

"But I'm just myself. I'm comfortable being myself. I'm an outspoken guy, but every team I've always been around, I've loved my teammates to death."

Mitchell was also in hot water with the league in 2012, when the CFL fined him for using derogatory terms against people of Chinese descent on Twitter.

The six-foot-six lineman signed with Montreal in February 2015. He was a CFL all-star in 2011.

Jones said the team needs to evaluate Mitchell's fitness before deciding how he would fit into their plans.

"I've got to go through everything and once everything comes up to the game day, coach Jones will make the proper assessments," Mitchell said.

"I trust whatever assessment he comes up with and then I'm just going to give him the best Khalif that he knows."

— With files from the Regina Leader-Post