According to UFC.com:

UFC President Dana White announced today another change to next weekend's main card. "Yoshihiro Akiyama will not be able to participate at UFC 128 due to the tragedy in Japan," said White.

"New Jersey native Dan Miller proves once again that he will fight anyone, anywhere, any time by agreeing to step up from the prelims to face Nate Marquardt," added White. "Marquardt has long been a top ten ranked middleweight and Miller jumped at the opportunity to face him."

Mar 19th, live on Pay-per-view from Newark, N.J.:

Nate "The Great" Marquardt (30-10-2)
Loss Yushin Okami - Decision (Unanimous) UFC 122
Win Rousimar Palhares - TKO (Punches) UFC FN 22
Loss Chael Sonnen - Decision (Unanimous) UFC 109

Dan Miller (13-4)
Win Joe Doerksen - Decision (Split) UFC 124
Win John Salter - Submission (Guillotine Choke) UFC 118
Loss Michael Bisping - Decision (Unanimous) UFC 114