Coming off its first loss of the season, No. 18 UCLA hosts Oregon on Saturday as both teams try to keep dimming college football playoff hopes alive. The Oregonian’s Andrew Greif answered five questions about the No. 12 Ducks.

1. Shortly before Oregon’s loss to Arizona, Mark Helfrich was dubbed a “quiet genius.” Was that a premature coronation of sorts, or does he simply need more time to guide the Ducks back to Chip Kelly-like levels?

It wasn’t premature to hail his intellect, because he’s regarded as one of the country’s smartest coaches on a pure intelligence level. But how that’s translated to coaching is muddled for critics, who see his 15-3 Pac-12 coaching record and believe that it should be 17-1, at worst. Honestly, he’s in a no-win situation as Chip Kelly’s successor, a point the “Quiet Genius” story deftly told. His 15-2 conference record entering last week’s game against Arizona tied Helfrich for the best conference coaching start since Pappy Waldorf at Cal in 1947. But then Oregon lost, giving him a third conference defeat — as many as Kelly had in his entire four-year run. You can sense Oregon fans getting restless that given all his intellect and talent on the rosters, the Ducks haven’t done more with it.

2. After holding opponents to 4.61 yards per play in 2013 — the seventh-best mark in the country — the Ducks are giving up 5.73 through five games. How much would you attribute the defensive drop-off to the coordinator change (Nick Aliotti to Don Pellum) versus personnel changes/injuries?

Players and coaches are steadfast that the 3-4 scheme has barely changed since Aliotti retired last January, but there is obviously some difference in play calling when a new coordinator takes over as he learns his comfort calling plays. A small trend many have noticed so far is Pellum’s reticence to blitz at times — against Washington State, the Ducks typically dropped eight into coverage. But this defense also lost three starters in its secondary, one at linebacker and three valuable rotation players on the defensive line from last season, and there are obviously kinks being worked out because of those new faces.

3. Marcus Mariota still looks as impressive as ever, particularly his 15-to-0 TD-to-INT ratio. How does he compare to his last season, and is his Heisman campaign still viable after that late-game fumble against the Wildcats?

I have to believe his Heisman campaign is still very much afloat because not only does everyone know his gaudy statistics, but the offensive line’s struggles due to injuries — three starting tackles have been injured — are also nationally known, too. For some voters, the depleted line might actually make his production even more impressive. His 71.1 completion percentage ranks fourth nationally, his passing efficiency is the best in the country and he accounts for 325.2 yards per game, which is 15th-best. Heisman Trophy candidacy seems to change every week, however, and the only surefire way to remain in the discussion is to win. If he does that and can put the two-fumble Arizona loss in the rear view, he’ll make it to New York.

4. Oregon only allowed 18 sacks last season and 19 the year before. This fall, it’s already given up 15, worse than any team in the Pac-12 except UCLA. What’s wrong, and what’s the outlook moving forward?

What’s wrong is the aforementioned injuries. The MASH unit: Starting left tackle Tyler Johnstone (ACL, lost in August); right tackle Andre Yruretagoyena (lower right leg in a cast, hurt against Michigan State); and left tackle Jake Fisher, who shifted from the right side to replace Johnstone (undisclosed leg injury, hurt against Wyoming). Without those players, along with injuries to two expected backups, too, the Ducks have used true freshman Tyrell Crosby at left tackle and former walk-on Matt Pierson, who played more golf than football in high school, at right tackle. Their play has been mixed, as one should expect. More troubling have been the errors by Oregon’s veterans like guard Hamani Stevens and All-American center Hroniss Grasu, who allowed sacks and been penalized in the last two games. Though the line was improved against Arizona — five sacks is better than the seven against WSU, at least — its outlook appears grim if Fisher can’t return soon.

5. How are the Ducks utilizing skill players this season compared to last? Has Royce Freeman lived up to preseason expectations?

Opposing fans will see familiar elements from Oregon’s offense this season and some new wrinkles, too. What’s recognizable is how offensive coordinator Scott Frost uses a small, shifty and speedy player in a hybrid receiver-runner role known as the “Tazer.” In years past, that role went to De’Anthony Thomas. This year, it’s standout freshman receiver and special teams stalwart Charles Nelson. The Ducks have such a wealth of depth at running back that it’s led to new uses not expected before the season, however, and the biggest example is using Byron Marshall at wide receiver. Yes, the same Marshall who ran for 1,038 yards and 14 touchdowns last season as a sophomore. He leads UO with 24 catches, and has 24 carries. This week Oregon officially moved Marshall to wide receiver on the depth chart, and though he’ll likely spend some time in the backfield, that seems to be his new home. That’s left Freeman, the true freshman, to carve out a big role at running back, where he gets more carries as the game goes on — 31 carries for 157 yards in the fourth quarter this year, most among UO running backs. With five touchdowns, he’s lived up to expectations as a bruising force, but he’s yet to crack 100 yards.