Asked to distinguish Mark Sanchez from John David Booty, Pete Carroll offered, “[Sanchez] has a huge arm. He can throw the ball a mile, and he loves to air it out…He’s apt to take some shots if they’re there.” While the play-calling focus for Sanchez in his first college start will probably be an extremely conservative one, Carroll reiterated that “we have a lot of stuff available, like we always do.” In prepared statement, Booty said, “I’ll be right there next to Mark the whole way to help him along. He’ll do a great job. He’s prepared himself well, he’s waited his turn and now he’s ready to play.” Read on for more from Thursday.

• Jeff Byers, originally slated to start at center against Arizona due to his experience in snapping the ball to Sanchez, practiced Thursday at the position but was unable to snap the ball because he can’t bend his thumb after smashing it between two helmets Wednesday. This leaves Matt Spanos (lacerated fingers) as the most likely starting candidate at center on Saturday, even though he’s sat out most of the week. Spanos is confident he can handle the exchanges, remarking, “I worked with Mark a bunch in spring ball when John David had surgery.”
• RB Stafon Johnson, widely acknowledged as the team’s best tailback, is not expected to play against Arizona, though he did practice sparingly Thursday. His foot injury, initially diagnosed as a deep bruise, has now been designated a sprain. Chauncey Washington will start in his place, with Hershel Dennis backing him up, Carroll said. Desmond Reed, Allen Bradford, and Joe McKnight will also be available.
• CB Shareece Wright confirmed that his hamstring pull will not be recovered sufficiently for him to play Saturday.
• Scott Wolf is reporting that freshman RB Mark Tyler aggravated his leg (which he fractured last year) and missed more than a day’s practice this week. He remains on track to redshirt.
• Carroll said that Thomas Williams and Clay Matthews would share the strong-side linebacker duties against Arizona.
• K David Buehler connected on three field goals (from 20, 33, and 37) but had another field goal attempt blocked, the team’s third such breakdown of the week.

USC goes to backup plan (LA Times)
Injury to USC’s Stafon Johnson is more serious (LA Times)
USC defensive end Jackson defends team captains (Long Beach Press-Telegram)
Can USC’s Sanchez temper gunslinger mentality? (Long Beach Press-Telegram)
It’s official: Sanchez to start at QB for Trojans (Orange County Register)
Insider: Williams’ late rise, Sanchez to start (Rivals, $)
About Tyler (Scott Wolf)
Sanchez to start at QB for USC (The Press-Enterprise)
Behind Sanchez, the Trojans hope to get back on track (Daily Trojan)