Josh Rosen – UCLA
The nation's No. 1 quarterback recruit in the 2015 class enrolled in time to compete for the starting job that came open with Brett Hundley's departure for the NFL. Rosen will battle last year's backup, Jerry Neuheisel as well as Asiantii Woulard for the top job. UCLA returns 10 starters on offense, which could make it even more enticing for Rosen to be the starter, with the blow being softened with so many returners and only Hundley needing replacing.
Jake Browning - Washington
The two-time California player of the year was going to challenge for playing time regardless, with the Huskies quarterback situation never really set in stone. But with Troy Williams transferring and Cyler Miles stepping away from the football program for an indefinite time frame, Browning now has the chance to win the starting job coming out of spring, but will battle redshirt freshman K.J. Carta-Samuels and game one starter Jeff Lindquist, a redshirt junior.
Jeremiah Mitchell - Washington State
The offense hasn't been an issue for the Cougars under Mike Leach, but the defense has been another story. The Cougars hit the JC ranks hard on defense this year, needing some immediate upgrades and with some losses on the defensive line, Mitchell's early enrollment gives him a leg up on impacting the lineup and the rotation immediately. The Riverside College product had nearly 25 tackles for loss the past two seasons and will bring immediate help to the Cougars line.
Isaac Whitney - USC
Whitney is another product of Riverside College and a mid-year enrollee for the Trojans. With Nelson Agholor leaving for the NFL as expected as well as George Farmer's unexpected early departure, that makes Whitney's presence much more important and he'll likely be in the rotation immediately and needed to be another weapon for Cody Kessler.
Anthony Fotu - Arizona
Fotu was one of the top JC defensive linemen in the country last fall and his mid-year graduation and enrollment at Arizona gives them a boost on the defensive line. The Wildcats were the surprise of the Pac-12 last year, winning the Pac-12 South and playing in the Fiesta Bowl but their defensive line was eaten up in their last two games so Fotu will have a chance to crack the starting lineup coming out of spring.
Instant Impact: Five From the Pac-12
Josh Rosen – UCLA