Unbeaten middleweight Aaron Simpson will lock horns with Tom Lawlor in a featured bout at UFC Fight Night 20 on Jan. 11 at the Patriot Center in Fairfax, Va. Ten matches are now official for the event.

A late bloomer at 35, Simpson has finished all six of his opponents as a professional, four of them inside one round. A two-time All-American wrestler at Arizona State University, he last appeared at UFC 102 in August, when a knee injury to Ed Herman led to a second-round technical knockout. Simpson trains at Arizona Combat Sports, alongside World Extreme Cagefighting lightweight champion Jamie Varner and “The Ultimate Fighter” Season 8 light heavyweight winner Ryan Bader.

Lawlor sprang a surprise submission victory on Simpson’s ACS teammate, CB Dollaway, at UFC 100 in July, earning a “Submission of the Night” bonus after putting away his favored opponent in 55 seconds. Unbeaten outside of a 2008 disqualification loss to Shane Primm, the 26-year-old Fall River, Mass., native has gone the distance only once in his career. Lawlor, a quarter-finalist on Season 8 of “The Ultimate Fighter,” was a three-time national wrestling champion at the University of Central Florida.

Another middleweight bout will pit Chris Leben against Jay Silva in what appears to be a pivotal showdown for both men.

Leben has lost back-to-back bouts, including an arm-triangle submission to Jake Rosholt at UFC 102 in August. The 29-year-old has been knocked out only once -- by UFC middleweight kingpin Anderson Silva -- in 24 career bouts. Leben holds notable victories against current Sengoku middleweight champion Jorge Santiago, welterweight standout Mike Swick and one-time UFC middleweight title challenger Patrick Cote.

Anchored at the Gazze Academy in Huntington Beach, Calif., Silva dropped a unanimous decision to Dollaway in his promotional debut at UFC Fight Night 19 in September. A dangerous stand-up fighter with improving ground skills, the 28-year-old has secured four of his five victories by knockout or TKO. Silva has never been finished.

A lightweight showdown between the world-ranked Gray Maynard and “The Ultimate Fighter” Season 5 winner Nate Diaz will headline UFC Fight Night 20, along with a 155-pound tilt pitting unbeaten fighters Efrain Escudero and Evan Dunham against one another.

UFC Fight Night 20
Monday, Jan. 11
Patriot Center
Fairfax, Va.

Gray Maynard vs. Nate Diaz
Efrain Escudero vs. Evan Dunham
Aaron Simpson vs. Tom Lawlor
Chris Leben vs. Jay Silva
Rick Story vs. Jesse Lennox
Jeremy Stephens vs. Nik Lentz
Kyle Bradley vs. Rafael dos Anjos
Tim Credeur vs. Mike Massenzio
Nick Catone vs. Steve Steinbeiss
Rory MacDonald vs. Michael Guymon