White: Penn vs. MacDonald will happen
That news comes from Dana White, who announced at the post-fight press conference of "UFC on FX 3" that the bout will serve as the co-main event.
The UFC president also stated that matchmaker Joe Silva will be talking to both fighters very soon to finalize the match up.
The bout came to fruition after MacDonald challenged the future Hall-of-Famer to a bout on The MMA Hour. Penn fired back, stating that he would take that fight and come out of retirement.
MacDonald last fought at UFC 145, defeating Che Mills via submissino due to strikes. Prior to that victory, the Canadian fighter earned impressive wins over Nate Diaz and Mike Pyle and a disappointing loss to current interim champion Carlos Condit.
Meanwhile, Penn has not seen action since October of last year. He retired after a unanimous decision loss to Nick Diaz. He was offered comeback fights against Josh Koscheck at welterweight and Gilbert Melendez at lightweight, in the UFC and Strikeforce, respectively. Ultimately, he turned down both contests.