TORONTO — The CFL and the Saskatchewan Roughriders will be keeping a close eye on controversial defensive lineman Khalif Mitchell, league commissioner Jeffrey Orridge said Thursday.

Any "inappropriate behaviour" from Mitchell, who has been sanctioned twice for violating the league's social media policy, "will result in his immediate dismissal," Orridge said in a statement.

The Riders signed Mitchell to their practice roster Wednesday, a move that drew criticism from Canadian Jewish organizations.

Mitchell hasn't played since being released by the Montreal Alouettes in June 2015. He was fined a month earlier over anti-Semitic posts on his Twitter account, which included a link to a Holocaust denial video.

Mitchell claims he was researching his "Hebrew Semitic backgrounds."

"I just think a lot of the reaction was based off of a lot of misinterpretations about myself that was far-fetched," Mitchell said Thursday.

"I mean a lot of people looking at me as somebody that the media portrayed as an anti-Semitic type of person. And all I was doing was finding my own Hebrew Semitic backgrounds and my own source of where I'm from. Like my mom's from the tribe of Juda, my dad's from the tribe of Benjamin. And so, through learning all those things and trying to find out who I am and find out where my lineage comes from, I just kind of got caught up in it."

Orridge said the CFL will be monitoring Mitchell's social media posts.

"Our social media policy expressly prohibits a current player, team or league employee from using social media, including the retweeting or reposting of someone else's comments, to condone discrimination, harassment or violence," Orridge said in a statement. "Since Mitchell has now returned to our league with another club, his new employer has reached out to the league office to assure us they too take this matter very seriously and any such inappropriate behaviour from Mitchell will result in his immediate dismissal.

"We too will monitor any commentary he may make as a member of our league. Such comments, which put the league’s reputation as a progressive and positive member of the community in question, will not be tolerated."

Mitchell seemed unfazed by Orridge's statement.

"Well I mean the league has their position and that's their position," he said. "I don't know what goes on in the league. The league is the league. That's their position, that's fine."

After being fined in 2015, Mitchell apologized in a joint statement by the CFL Players' Association and B'nai Brith Canada, saying it was "a learning moment for me." He agreed to work with B'nai Brith, a Jewish human rights organization, to "educate myself about this and other human rights matters.''

But Shimon Koffler Fogel, CEO of the Centre for Israel and Jewish Affairs, said Wednesday there was 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 it deemed troubling. Mitchell, 31, said he was aware of the reputation he brings to Saskatchewan.

"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."

The six-foot-five, 316-pound Mitchell, a 2011 CFL all-star with B.C., also landed in hot water with the CFL in 2012 when he was fined for using derogatory terms against people of Chinese descent on Twitter.

Chris Jones, the Riders head coach/GM, told reporters in Regina on Thursday he has spoken at length with Jewish community leaders in Toronto and fully understands Orridge's statement.

"I spoke with the folks in Toronto and we had a really good, probably about an hour-long conversation," Jones said. "We're here to play football and to coach football . . . if there's anything that's said then Khalif won't be here."

Saskatchewan (1-8) resumes league action Sunday hosting the Winnipeg Blue Bombers (5-4), who've won four straight. Jones was non-commital whether Mitchell will be on the Riders' active roster for the game.

"We'll see," Jones said. "He's got a ways to go conditioning-wise so we'll watch the film and make our evaluations off the film."

Jones and Mitchell have a history together. Mitchell played for the Toronto Argonauts in 2013 when Jones was their defensive co-ordinator.

"I had Khalif on our football team in Toronto and he did an outstanding job and didn't have a single bit of trouble with us ever," Jones said. "Khalif is one of those guys, he's more of a team guy than people would anticipate or what they know about him.

"I had him for 12 months so I know what we need to do and how we need to handle Khalif."

— With files from Evan Radford in Regina.