Fraser, 27, has one assist, a minus-8 rating and 33 penalty minutes in 15:12 of ice time in 19 games. He last played Jan. 9 and has been a healthy scratch in 19 of the Leafs' past 20 games.
He sustained a knee injury in the Leafs' second game of the season, Oct. 2 against the Philadelphia Flyers, and missed a month, and in November missed two games with a knee injury.
"I'm happy to get to play for another organization with extremely passionate fans," Fraser told the Oilers' website. "I'm very excited. I'm confident I can provide something the Oilers may be missing. ... Most of my success comes from my size and aggression."
Last season Fraser had eight assists and a plus-8 rating in 45 games and played in the Leafs' first four Stanley Cup Playoff games. He was injured in Game 4 against the Boston Bruins when he was hit in the head by a puck and missed the remainder of the postseason.
In parts of six seasons with the New Jersey Devils and Maple Leafs, Fraser has 17 points and a plus-12 rating in 162 games. He also has five games of Stanley Cup Playoff experience.
Hartikainen, 23, was a 2008 sixth-round pick (No. 163) of the Oilers. He had one goal and two assists in 23 games with the Oilers last season, and in parts of three seasons with Edmonton had six goals and 13 points in 52 games. He's playing for Salavat Yulaev in the Kontinental Hockey League this season, where he has 13 goals and 27 points in 43 games.
Abney, 22, was a 2009 third-round pick (No. 82) of the Oilers. The 6-foot-5, 219-pounder has one goal and three assists in 20 games with the Bakersfield Condors of the ECHL. He's also spent time with the Oilers' American Hockey League affiliate, the Oklahoma City Barons, in his three professional seasons.