Both signal-callers will be in the spotlight Saturday night as the 18th-ranked Beavers look to win their sixth straight trip to Tucson and post their first 3-0 start in 10 seasons.
Mannion is averaging 327.5 yards to lead the conference, although Oregon State (2-0, 1-0) is the only Pac-12 team yet to play at least three games.
The sophomore hurt his throwing shoulder in last Saturday's 27-20 victory at then-No. 19 UCLA. He did not take part in practice Monday, but said he would be OK to face the Wildcats.
Mannion led Oregon State to a 37-27 home win over Arizona (3-1, 0-1) last season, completing 32 of 41 passes with two touchdowns and two interceptions.
"He is an experienced guy, a big guy who can make all the throws, and he is tough in the pocket as well," Arizona coach Rich Rodriguez said.
Rodriguez is just as concerned about the status of Scott, who had a 71.5 completion percentage and 995 passing yards with seven touchdowns and one interception during the Wildcats' 3-0 start.
The senior and the team cooled off last Saturday in a 49-0 loss at then-No. 3 Oregon. Scott completed 22 of 44 passes for 210 yards with a career-high three interceptions, taking his season average down to 301.3 yards.
Scott suffered a hip injury in the first quarter. That limited him to nine yards on five carries after the option quarterback averaged 63.3 yards on the ground in the first three games.
"Matt got a little sore during the first quarter," Rodriguez said. "We weren't trying to run him a lot anyway, but after the first quarter, we couldn't do things that we normally would do with Matt."
Getting untracked on the ground could be difficult Saturday even though Arizona tailback Ka'Deem Carey is third in the conference with 105.8 yards per game. The Beavers own the nation's second-best run defense in limiting foes to an average of 53.5 yards, and they held Johnathan Franklin - the Pac-12's top rusher - to a season-low 45 yards last week.
That kind of defense is a big reason why Oregon State has moved into the rankings for the first time since Oct. 11, 2010. Both of the Beavers' victories have been over ranked opponents, and the team is enjoying some national attention.
"It's a sign of good things actually, it's just a matter of how you handle it," coach Mike Riley said. "We've just got to keep the theme of this team together, which is working hard, getting ready to play."
Arizona, meanwhile, fell out of the Top 25 following the loss to the Ducks. The Wildcats reached the red zone six times, but four turnovers contributed to their first regular-season shutout loss since 2005.
"Every time you're in the red zone you expect to score and we just couldn't make it happen," Scott said. "We couldn't finish drives and we couldn't execute."
After failing to contain Oregon, Arizona will face the conference's top receivers next. Brandin Cooks and Markus Wheaton are ranked first and second in the Pac-12 with 127.5 and 118.5 receiving yards per game, respectively.
"They had a lot of explosive plays last week, and they have some fast guys playing on the perimeter," Rodriguez said. "We have to play them very disciplined."
Mannion will get his first look at the Wildcats' "3-3-5" defense, but he insists he has seen similar schemes before.
"You don't really want to psyche yourself out about it just because they call it something a little different," Mannion said. "Are there differences? Sure. But are there also a lot of similarities? Yes."
Riley, meanwhile, has no explanation for the Beavers' past success in Tucson.
"It all matters about this game, this Saturday, that's all there is to it," Riley said. "History is fine, everybody can look at it but it doesn't have really any bearing on this game."
The Wildcats figure to be fired up as they will wear copper helmets. It's the first time the team has not had a helmet predominantly colored white, blue or red.
"It's pretty cool," center Kyle Quinn said. "Being a history major, I know the importance of copper to the state and how big the mining industry is, so it's going to be great to be able to represent that."
- Sean Mannion