Introduction
UFC 183: Silva vs. Diaz. January 31, 2015. MGM Grand Garden Arena, Las Vegas. Anderson Silva returned to the Octagon for the first time since breaking his leg at UFC 168 on December 28, 2013 — a 13-month absence. His opponent was Nick Diaz, who had been out since losing to Georges St-Pierre at UFC 158 in March 2013. Silva won a unanimous decision (50-45, 50-45, 49-46) by dissecting Diaz with leg kicks and outstriking him over five rounds.
The result was subsequently overturned to a No Contest. Silva tested positive for drostanolone and androsterone (anabolic steroids) in an out-of-competition test administered on January 9. Diaz tested positive for marijuana metabolites post-fight — his third such positive result in his career. Both received NSAC suspensions; Silva for one year and Diaz for five years (later reduced to 18 months). The fight is officially recorded as a No Contest.
In the co-main event, Luke Rockhold submitted Lyoto Machida in round two, positioning himself as the No.1 MW title contender. Chris Weidman held the MW belt and was watching from outside the cage.
Contents
1. Introduction
2. Quick Stats
3. The Build-Up
4. Main Event
5. Co-Main Event
6. Full Results
7. Bonuses & Awards
8. Records & Milestones
9. Legacy & Impact
10. FAQ
11. References
Quick Stats
Date: January 31, 2015
Venue: MGM Grand Garden Arena, Las Vegas, Nevada, USA
Main Event: Anderson Silva vs. Nick Diaz — Middleweight (non-title; Silva’s return from UFC 168 leg break)
Official Result: Silva def. Diaz — UD (50-45, 50-45, 49-46) — OVERTURNED TO NO CONTEST (both fighters failed drug tests)
Drug tests: Silva: drostanolone + androsterone (anabolic steroids) — out-of-comp test Jan 9; Diaz: marijuana metabolites (3rd positive in career)
Suspensions: Silva: 1 year; Diaz: 5 years (reduced to 18 months + $100k fine on appeal)
Co-Main: Luke Rockhold def. Lyoto Machida — Sub R2 — MW; Rockhold positions as MW title contender
Bonuses: FOTN: Leites/Boetsch ($50k each); POTN: Anderson Silva + Thiago Alves ($50k each) — Silva’s bonus rescinded after his failed drug test
The Build-Up
Anderson Silva’s left leg had broken on December 28, 2013 when Chris Weidman checked his kick at UFC 168. Surgery was performed on both the tibia and fibula. The UFC and Silva’s camp indicated he would return to competition; a new 15-fight contract was announced. The fight against Nick Diaz was announced in October 2014 as a non-title middleweight bout — a ‘superfight’ between two of the sport’s most iconic names.
Nick Diaz had been inactive since his UFC 158 loss to Georges St-Pierre in March 2013. He had reportedly been retired. Dana White convinced him to return. Diaz’s fanbase ensured the fight generated significant commercial interest despite neither man holding a championship.
Main Event
Anderson Silva vs. Nick Diaz — Middleweight (No Contest)
Silva was methodical from the opening bell, using taekwondo-style leg kicks and precise jabs to control distance. Diaz taunted throughout — lying on his back at one point, turning his back, inviting exchanges. Silva’s usual showboating was absent; he was focused and businesslike across all five rounds.
The decision was 50-45, 50-45, 49-46 for Silva. Post-fight, Silva broke down in tears in the Octagon, overcome with emotion at his return. The moment was widely celebrated as one of the sport’s most human post-fight scenes. It was later rendered irrelevant by the drug test results.
On February 3, 2015, the UFC announced Silva had tested positive for drostanolone metabolites in an out-of-competition test administered on January 9 — three weeks before the fight. A subsequent fight-night test also returned a positive result. Diaz’s post-fight test showed elevated marijuana metabolites — his third such positive result, following 2007 and 2012. The result was overturned to a No Contest.
Co-Main Event
Luke Rockhold vs. Lyoto Machida — Middleweight
Rockhold entered as a former Strikeforce MW Champion making his statement in the UFC. Machida was a former LHW Champion and respected MW contender. In round one, Rockhold landed precise strikes while controlling the clinch. In round two, he secured a takedown, moved to back control, and finished Machida with a rear-naked choke. The submission established Rockhold as the leading MW title contender and the inevitable next challenger for Weidman’s belt.
Full Results
Preliminary Card
Thiago Alves def. Jordan Mein — TKO (body kick + punches) — R1, 4:04 — WW; POTN ($50k to Alves)
Ed Herman def. Derek Brunson — Decision (Split) — R3 — MW
John Lineker def. Ian McCall — Decision (Split) — R3 — Flyweight
Thiago Santos def. Andy Enz — TKO — R2 — MW
Rafael Natal def. Tom Watson — Decision (Unanimous) — R3 — MW
Joe Riggs def. Ron Stallings — No Contest — originally Riggs win; overturned (Riggs failed drug test) — MW
Sean Strickland def. Tom Breese — Decision (Unanimous) — R3 — WW
Main Card
Jordan Mein originally listed — see prelims. Main card opener:
Costas Philippou def. Lorenz Larkin — Decision (Unanimous) — R3 — MW
Thales Leites def. Tim Boetsch — Sub (guillotine choke) — R3 — MW; FOTN ($50k each)
Luke Rockhold def. Lyoto Machida — Sub (RNC) — R2, 2:31 — MW; Co-Main; Rockhold MW title contender
Middleweight Bout — Main Event (No Contest)
Anderson Silva vs. Nick Diaz — No Contest (originally UD 50-45, 50-45, 49-46 for Silva; overturned after both fighters failed drug tests)
Bonuses & Awards
Fight of the Night: Thales Leites vs. Tim Boetsch — $50,000 to each fighter.
Performance of the Night: Anderson Silva + Thiago Alves — $50,000 each. Silva’s bonus was rescinded following his failed drug test.
Records & Milestones
Anderson Silva — first fight back from UFC 168 leg break; result overturned to NC.
Nick Diaz — third career drug test positive for marijuana metabolites (previous: 2007 and 2012); 5-year suspension reduced to 18 months + $100k fine on appeal.
Luke Rockhold — win over Lyoto Machida confirmed him as the No.1 MW contender; Rockhold subsequently won the MW title from Chris Weidman at UFC 194 in December 2015.
Legacy & Impact
UFC 183 is the event where the drug-testing era’s most instructive story played out. Both fighters in the main event failed. The emotional post-fight breakdown of Anderson Silva — one of the most affecting post-fight scenes in the sport’s history — became a footnote to a drug test.
The fight itself had been straightforward: Silva was controlling and methodical, Diaz taunted but never threatened. The result on the scorecards was not close. None of that matters in the official record. What UFC 183 actually delivered was Luke Rockhold’s submission of Lyoto Machida and the confirmation of Weidman’s next mandatory challenger.
FAQ
Why was the UFC 183 main event result overturned to No Contest?
Both Anderson Silva and Nick Diaz failed drug tests related to UFC 183. Silva tested positive for drostanolone and androsterone (anabolic steroids) in an out-of-competition test on January 9, 2015. Diaz tested positive for marijuana metabolites post-fight, his third such positive in his career. The NSAC overturned the result to No Contest.
What steroids did Anderson Silva test positive for at UFC 183?
Silva tested positive for drostanolone and androsterone, both anabolic steroids, in tests connected to UFC 183.
Who won the UFC 183 co-main event?
Luke Rockhold submitted Lyoto Machida by rear-naked choke in round two, establishing himself as the No.1 middleweight contender. He went on to win the title from Chris Weidman at UFC 194.
Did Nick Diaz get a long suspension for UFC 183?
The NSAC initially gave Diaz a five-year suspension for his third marijuana-related positive, a penalty widely criticised as disproportionate. It was later reduced to 18 months plus a $100,000 fine on appeal.