The UFC on FOX event in Seattle has a pair of new fights and a heavyweight bout has been added to UFC 162.

Tarec Saffiedine, the final Strikeforce welterweight champion, makes his UFC debut against Robbie Lawler at Key Arena on July 27. Additionally, lightweight Bobby Green returns to the Octagon and faces Danny Castillo. Meanwhile, Shane Del Rosario and Dave Herman will square off at UFC 162 on July 6 in Las Vegas.

The UFC announced the bouts via Twitter on Thursday.  Saffiedine (14-3), who trains with Dan Henderson at Team Quest in Temecula, Calif., has won four straight bouts and seven of his past eight. His most recent win was an upset victory over Nate Marquardt for the welterweight title on the final Strikeforce card. Lawler (20-9, 1 no-contest), meanwhile, is a veteran of the sport. The former EliteXC middleweight champ returned to the UFC at UFC 157 in February after a nine-year absence and scored a brutal knockout of Josh Koscheck.

Green (20-5) seemed long pegged as a Southern California journeyman, but he's come into his own over the past two years. The brawler has won five straight, including a victory over Jacob Volkmann in his UFC debut on Feb. 2, which earned him submission of the night honors. Castillo (15-5), meanwhile, is a Team Alpha Male fighter who has won four of his past five bouts, most recently a decision victory over Paul Sass.

Del Rosario (10-2) vs. Herman (20-5), frankly, could be a fight in which both are looking to keep their jobs. Del Rosario is 0-2 in the UFC and has suffered bad knockouts to Stipe Miocic and Pat Barry in the process. Herman has been finished in his past three UFC fights and tested positive for marijuana after his October loss to Antonio Rodrigo Nogueira.

Event results for UFC 153, which took place Saturday at the HSBC Arena in Rio de Janeiro.

Main Card

• Anderson Silva def. Stephan Bonnar via TKO (strikes) - Round 1, 4:40
• Antonio Rodrigo Nogueira def. Dave Herman via submission (armbar) – Round 2, 4:31
• Glover Teixeira def. Fabio Maldonado via TKO (doctor's stoppage) - Round 2, 5:00
• Jon Fitch def. Erick Silva via unanimous decision (30-27, 29-28, 29-28)
• Phil Davis def. Wagner Prado via submission (anaconda choke) - Round 2, 4:29

• Demian Maia def. Rick Story via submission (rear-naked choke) - Round 1, 2:30
• Rony Jason def. Sam Sicilia via TKO (strikes) - Round 3, 4:15
• Gleison Tibau def. Francisco Trinaldo via unanimous decision (29-28, 29-28, 29-28)
• Diego Brandao def. Joey Gambino via unanimous decision (30-27, 30-27, 30-27)
• Sergio Moraes def. Renee Forte via submission (rear-naked choke) - Round 3, 3:10

• Chris Camozzi def. Luiz Cane via unanimous decision (29-28, 29-28, 29-28)
• Cristiano Marcello def. Reza Madadi via split decision (28-29, 29-28, 30-27)

The UFC's traditional pre-event show returns Wednesday with the debut of "Countdown to UFC 146: Dos Santos vs. Mir" on FUEL TV.

The half-hour special debuts on Wednesday morning at midnight ET. Same-day replays air in more viewer-friendly slots of 5 p.m. ET and 10 p.m. ET, also on FUEL TV.

UFC 146 takes place Saturday, May 26 at Las Vegas' MGM Grand Garden Arena. A heavyweight title fight between current champ Junior Dos Santos and former titleholder Frank Mir headlines the pay-per-view main card, which follows prelims on FX and Facebook.

Additional replays of "Countdown to UFC 146" air Thursday (8 p.m. ET) and Friday (1:30 a.m. ET) on FUEL TV.

Unlike the FX-aired "UFC Primetime" series, which focuses solely on the evening's main-event participants, "Countdown to UFC 146" also takes an in-depth look at the training camps and backgrounds of some of the evening's other main-card fighters.

Featuring a historic all-heavyweight main card, UFC 146's lineup has undergone a major overhaul since it was first announced but still hosts an enticing five-bout pay-per-view lineup. In addition to the main event, UFC 146 also boasts Antonio Silva vs. Cain Velasquez, Dave Herman vs. Roy Nelson, Shane Del Rosario vs. Stipe Miocic and Lavar Johnson vs. Stefan Struve.

The injury bug has bitten again, and this time its target was UFC 146, which underwent two more changes today.

After much reshuffling on the all-heavyweight main card, Roy "Big Country" Nelson (16-7) now has his third opponent since the event was announced. Gabriel Gonzaga is out with an injury, just 8 days after being slotted to fight Nelson after Nelson's original opponent, Bigfoot Silva, was plucked for another bout. Hirsute heavyweight Dave Herman (21-3) will now fill in against the TUF 10 winner.

On the undercard, lightweight contender Evan Dunham has also been injured, forcing him to withdraw from his much-anticipated bout against Edson Barboza (10-0). The change opens the door for the Zuffa return of former WEC champion Jamie Varner (19-6-1). Varner has racked up three impressive wins in the last year, all finishes in under two minutes.

UFC 146 takes place May 26 at MGM Grand Garden Arena in Las Vegas.

Event results for UFC on Fuel 1, which takes place Wednesday at Omaha Civic Auditorium in Omaha, Neb.

Main Card

• Jake Ellenberger  def, Diego Sanchez via decision (29-28x3)
• Stefan Struve def. Dave Herman via TKO (punches), Rd 2, 3:52
• Ronny Markes def. Aaron Simpson via split-decision (29-28x2, 28-29)
• Stipe Miocic def. Phillip De Fries via KO (punches), Rd 1, 0:43
• T.J. Dillashaw def. Walel Watson via decision (30-25x2, 20-26)
• Ivan Menjivar def. John Albert via submission (rear-naked choke), Rd 1, 3:45

Preliminary Card

• Jonathan Brookins def. Vanger Rocha via KO (punches), Rd 1, 1:32
• Justin Salas def. Anton Kuivanen decision (30-27x2, 29-27)
• Buddy Roberts vs. Sean Loeffler (cancelled due to Loeffler suffering an ankle injury)
• Tim Means def. Bernando Magalhaes via decision (30-26x2, 30-27)