TCU coach Gary Patterson won't have the services of QB Casey Pachall, who was suspended indefinitely following an arrest on suspicion of driving while intoxicated early Thursday morning. (AP)

Iowa State (3-1, 0-1 Big 12) at No. 15 TCU (4-0, 1-0 Big 12)

Kickoff: Saturday, 3:30 p.m. ET (Fox Sports Network)

Spread: TCU by 10

Watchability: If you're a fan of old-school, grind-it-out football and last week's West Virginia-Baylor game offered enough offense to last you a month, this is a good game to watch. Both teams have strong defenses, and both have offenses that have struggled in stretches as well. Factor in the suspension of TCU starting QB Casey Pachall, who was arrested on suspicion of driving while intoxicated in the overnight hours of Thursday morning, and you have all the makings of a low-scoring slugfest.

Shining stars: Iowa State: RBs James White and Shontrelle Johnson. One of the most puzzling things about last week's 24-13 loss to Texas Tech was the lack of commitment to the running game. White and Johnson each had only nine carries -- and they fared well when they did get the ball, combining to average better than 5.6 yards per attempt. Both backs are averaging 5.0 yards per carry or better this season. If ISU hopes to get its struggling offense on track, it may want to start by running early and often. TCU: DE Devonte Fields. Most of the attention on the Horned Frogs' defense goes to preseason All-Big 12 pick Stansly Maponga, but Fields -- a true freshman -- has led the way statistically thus far. He had 2.5 sacks and four tackles for a loss in last week's rain-soaked win over SMU. For the season, he is fourth on the team in tackles (17) but is easily its leader in tackles for loss (8.5) and sacks (5.0) -- more than twice the number of any of his defensive teammates in both stats. He also has a forced fumble to his credit.

Who could steal the show: Iowa State: QB Steele Jantz. If Jantz steals the show, it will probably be in a way Cyclones fans would like to forget. The senior struggled mightily against Texas Tech last week, completing only 10 of his 20 passes for a mere 73 yards. Most problematic, however, was the fact Jantz threw three interceptions. He now has thrown as many interceptions as touchdowns this season -- seven each. With the offense struggling enough as it is, Jantz can't afford to turn the ball over if ISU hopes to pull the upset. TCU: WR Brandon Carter. Most figured Josh Boyce would lead the Horned Frogs' passing attack this season, but Carter has played well in the team's first four games, averaging 77 receiving yards and a touchdown per game. In a game in which TCU has uncertainty at quarterback given the suspension of Pachall, Boyce's ability to serve as a vertical threat is that much more important.

You going? Ranking the road trip: The game will serve as TCU's first-ever home contest in the Big 12, so it should be a momentous occasion inside the newly renovated Amon G. Carter Stadium. The Horned Frogs have sold out 10 consecutive home games and had only a few seats remaining when the Cyclones returned a few tickets, so it figures to be another strong showing from the TCU faithful.

Magic number for Iowa State: 157:40. That's how long the Cyclones went without allowing a touchdown before Texas Tech broke through with an 11-yard scoring pass just before halftime last Saturday. Indeed, TCU isn't the only team that comes into this game with a strong defense. Iowa State is 17th in the country in scoring defense, allowing 14.0 points per game.

Magic number for TCU: 7.3. That's the scoring average the Horned Frogs are allowing on a per-game basis, good enough for No. 2 in the nation in scoring defense. Iowa State hasn't exactly been strong on offense thus far this season -- it managed only nine points in a win over Iowa and finished with fewer than 200 yards of total offense last week -- so TCU should have a chance to again dominate with its defense.

This game comes down to: Which team can get going offensively? The Cyclones managed only 189 yards of total offense in last week's loss to Texas Tech. If Iowa State harbors hopes of competing with the Big 12's better teams, it must get more production from its offense. TCU's offense hasn't exactly been spectacular to start the season. Now the team has uncertainty at quarterback due to Pachall's suspension. Former backup QB Matt Brown was moved to wide receiver late in the preseason, meaning redshirt freshman Trevone Boykin is next in line for time at the position. Points could be at a premium for both teams.

Prediction: Iowa State 17, TCU 13

For more up-to-the-minute news and analysis from Big 12 bloggers C.J. Moore and Patrick Southern, follow @CBSSportsBig12 on Twitter. You can also follow C.J. (@cjmoore4) and Patrick (@patricksouthern).