In return, the Oilers will receive defenseman Philip Larsen and a seventh-round pick in the 2016 NHL Draft.
Horcoff, a 34-year-old center, has played 796 NHL games, all with the Oilers, who chose him in the fourth round (No. 99) of the 1998 NHL Draft. He has 162 goals and 285 assists since making his NHL debut on Dec. 6, 2000.
"In this business, every day you come to work and try to get better. We're looking at other options, but this adds two center-icemen to our roster and we're excited about that," Nill said. "Both are right-handed shots, which you don't find a lot of. This gives us a good mix at center. Really our one weakness here in Dallas is we had no depth at center ice."
Larsen, 23, played 32 games for Dallas in 2012-13, with five points and a minus-10 rating. In 2011-12, he was a plus-11 in 55 games, with 11 points.