One Big Question for Lincoln Riley Entering Year Five at USC

The 2026 season will be a pivotal fifth year for USC Trojans coach Lincoln Riley. Heading into a season filled with College Football Playoff expectations, what is the biggest question for Riley and the Trojans entering year five?

Sep 13, 2025; West Lafayette, Indiana, USA; Southern California Trojans head coach Lincoln Riley stands on the sidelines during the first quarter against the Purdue Boilermakers at Ross-Ade Stadium. Mandatory Credit: Marc Lebryk-Imagn Images | Marc Lebryk-Imagn Images

Following a 9-4 finish in 2025 that featured its fair share of highs and lows for the USC Trojans, coach Lincoln Riley enters a pivotal fifth season that could determine his future in Los Angeles. In his four seasons with the Trojans, Riley has posted a 35-18 coaching record, and many Trojans fans believe that anything short of reaching the College Football Playoff in his fifth year is a failure.

Heading into a pivotal 2026 season, several questions will center around Riley and USC. The biggest one, however, is USC's defense, and can they play to the best of their ability?

Nov 7, 2025; Los Angeles, California, USA; Southern California Trojans head coach Lincoln Riley watches game action against the Northwestern Wildcats during the second half at the Los Angeles Memorial Coliseum. Mandatory Credit: Gary A. Vasquez-Imagn Images | Gary A. Vasquez-Imagn Images

There is no doubt that Riley is a great offensive mind and has had some great offenses throughout his coaching career, both at Oklahoma and USC. The one thing, however, that has been holding his teams back and for which he gets criticized the most is the performance of his defense. 

USC's Defensive Issues Under Lincoln Riley

Nov 7, 2025; Los Angeles, California, USA; Southern California Trojans head coach Lincoln Riley watches game action against the Northwestern Wildcats during the second half at the Los Angeles Memorial Coliseum. Mandatory Credit: Gary A. Vasquez-Imagn Images | Gary A. Vasquez-Imagn Images

In his four seasons as coach for the Trojans, defense has held USC back, as they have only had one year winning 10 games or more, which came in Riley’s first season in Los Angeles. Even in that season, where USC finished with an 11-3 record led by the brilliance of Heisman-Trophy winning quarterback Caleb Williams, defense held them back, especially in the two losses to the Utah Utes, which kept the Trojans out of the CFP. 

MORE: USC Defense Takes a Hit at Linebacker with Late Transfer Portal Exit

MORE: NIL Impact Of Terrell Anderson's Transfer To USC

MORE: USC’s Quarterback Room Following Transfer Portal Shakeup

SIGN UP FOR OUR NEWSLETTER HERE!

Heading into the 2026 season, the performance of USC’s defense will be the biggest key in leading the Trojans to an appearance representing the Big Ten in the CFP. After the departure of D’Anton Lynn to Penn State, USC’s new defensive coordinator and the defensive scheme he brings to the Trojans could make the difference.

Despite not reaching their goal of making the CFP under Lynn’s leadership on defense, USC's defensive performance showed promising strides in its physicality, which is why the defensive coordinator hire for the Trojans is extremely important this offseason. 

Top Returners and Transfer Portal Additions On USC's Defense

Sep 20, 2025; Los Angeles, California, USA; Southern California Trojans defensive end Braylan Shelby (10) reacts after sacking Michigan State Spartans quarterback Aidan Chiles (2) during the second half at the Los Angeles Memorial Coliseum. Mandatory Credit: Gary A. Vasquez-Imagn Images | Gary A. Vasquez-Imagn Images

USC has several returning players on defense who look to take the next step in 2026 and deliver the Trojans a successful championship season. Top returners that could make the ultimate difference for USC on their defensive front include defensive end Braylan Shelby and Kameryn Crawford, along with defensive tackles Jahkeem Stewart and Floyd Boucard. 

The performance of USC’s secondary may be the most important group on the Trojans defense heading into the 2026 season. In several games this season, especially their three regular-season losses to the Illinois Fighting Illini, No. 11 Notre Dame Fighting Irish, and No. 5 Oregon Ducks, big pass plays plagued the Trojans defense. Key returners in USC’s secondary include cornerback Marcelles Williams and defensive back Christian Pierce. 

Sep 6, 2025; Seattle, Washington, USA; Washington Huskies linebacker Deven Bryant (17) tackles UC Davis Aggies running back Jordan Fisher (20) during the second quarter at Husky Stadium. Mandatory Credit: Joe Nicholson-Imagn Images | Joe Nicholson-Imagn Images

To strengthen their defensive roster, USC added several impactful transfer players that Trojan fans hope will make an immediate impact. Key additions for the Trojans include transfer cornerbacks Iowa State’s Jontez Williams and Oklahoma State’s Carrington Pierce.

The Trojans also bring in Washington transfer linebacker Deven Bryant, Penn State defensive end Zuriah Fisher, and Michigan State defensive lineman Alex VanSumeren.