As things look on paper for Saturday’s Stanford-Oregon State game, you’d almost have to say that the first team to score a touchdown wins.

The two best defenses in the Pac-12 go up against two of the worst offenses. Even though both teams have veteran quarterbacks – Kevin Hogan for Stanford and Pleasanton native Sean Mannion for Oregon State – they’re 11th and 12th in the league in third-down conversions.

Stanford has the added distinction of being the worst red-zone team in the conference.

Why the Cardinal (4-3, 2-2 Pac-12) are a 13 ½-point favorite over the Beavers (4-2, 1-2) in the 12:30 p.m. matchup at Stanford Stadium is anybody’s guess.

Coming off last week’s 26-10 loss at Arizona State, Cardinal head coach David Shaw said, “We can’t just continue to do what we’ve been doing. We’ve got to make some changes.’’

He wasn’t about to tip off his hand, but one change he might make is to send the tailback or the fullback out on pass patterns, even just short ones as check-down options for Hogan. ASU put plenty of pressure on him, and often there didn’t seem to be a safe outlet receiver.

It isn’t even Halloween, and already the Cardinal have their backs to the wall.

“No one wanted the season to go how it is going so far, but we’ve got to move on from the losses,’’ offensive tackle Kyle Murphy said. “We still control our own destiny in the Pac-12.’’

That is, they could still reach the conference title game by winning the final five games, including beating Oregon in Eugene next week. But all it will take is one slipup before the Cardinal need to start mulling the merits of the Royal Purple Las Vegas Bowl.

They’ll need to get Ty Montgomery and Devon Cajuste (back from missing last week’s game with an apparent concussion) on track. Stanford appropriately is throwing more than it has in the past; it just can’t seem to spring its playmakers for big gains. Montgomery hasn’t scored in the last three games.

“That’s what’s really eating me,’’ Shaw said. “With the personnel we have there’s no reason should score 10 points against anybody we play.’’

With David Parry joining Aziz Shittu on the injury list, the defensive line is in tough shape. Freshman Harrison Phillips takes over at the nose and will join ends Henry Anderson and Blake Lueders in trying to get a push on Mannion.

The Beavers’ 6-foot-5 quarterback is only eighth in the conference in passing yards per game (262.7), and he has almost as many interceptions (5) as touchdown passes (7). And this is a guy who’s just 316 yards from breaking Matt Barkley’s Pac-12 career record of 12,327 yards. OSU badly misses All-American wide receiver Brandin Cooks, now with the Saints.

Mannion’s arm remains top-notch, Shaw said. “Everybody within 50 yards is a viable receiver, from sideline to sideline,’’ he said. “Even when they struggle, you never know when he’s going to pop one over the top of your defense.’’

Storm Woods, who has split the main ball-carrying duties with former De La Salle-Concord athlete Terron Ward, has been hampered by a knee injury but is expected to play.