Freshman Calen Bullock to start in USC debut as S Isaiah Pola-Mao inactive

USC redshirt senior starting safety Isaiah Pola-Mao is not active for the Trojans' season-opener today vs. San Jose State due to health and safety reasons, TrojansSports.com confirmed.

USCFootball.com's Keely Eure first reported the news.

Freshman Calen Bullock will start in Pola-Mao's place at free safety, in his Trojans debut, becoming the first USC true freshman to start at safety in a season opener since Su'a Cravens in 2013.

Redshirt freshman Xavion Alford was listed as Pola-Mao's backup on the team's official depth chart released Thursday, but Bullock has been the most impressive of the Trojans' young safeties so it's not a surprise he gets the nod.

Here's what USC safeties coach Craig Naivar said about Bullock's development when asked this week:

“He, just like the young guys, has done a really good job investing the time over the spring, jumping right into learning the system because it's got a lot of complexity to it as far as understanding all the checks and adjustments," Naivar said. "And it's like learning algebra. You better know what Step A is and Step B because once you get to D if you don't know C you're in trouble. He's done a really, really good job with that which allows us to not have training wheels on what we're doing and really just run the package when those guys are in there."

It also won't be a surprise to see the Trojans rotate several safeties into the game to get Alford, a transfer from Texas, and Auburn transfer Chris Thompson Jr. some experience.

With Pola-Mao out, USC has two new starters at safety in Bullock and redshirt junior Chase Williams, who at least has some notable prior experience and has been locked in with the first-team defense since the start of spring.