ANN ARBOR, Mich. -- Michigan reaches the red zone and things change. The play calls look less like the shotgun, three and four wide receiver sets the Wolverines often run as they move quarterback Denard Robinson and the Michigan offense up and down the field.
When Michigan goes inside the opponent's 20 yard-line, it starts mixing it up -- bouncing between shotgun and the I-formation, between multiple wide receiver and tight end packages.
Michigan offensive coordinator Al Borges' offense fits perfectly because he throws sometimes as many as 20 different offensive sets at an opponent during a game. Thus far, his red zone play decisions have worked.
Michigan is one of 13 FBS teams to be perfect this season inside the red zone. Through four games, the Wolverines are 13-of-13 -- one of six BCS schools to be perfect. Michigan was also close to perfect last season through four games as well, converting 18 of 19 red zone chances.
This year's Michigan numbers are more impressive when you consider the Wolverines have scored touchdowns on 12 of their 13 red zone possessions.
"I don't know if there is a magical answer," Michigan coach Brady Hoke said. "Part of it is always you have some pretty good luck. I think we're blocking decently.
"I think the different options that Al presents to some degree with any offense makes it tougher to defend."
Those options all start with Robinson, the nation's leading rusher, at quarterback. His ability to run and pass, especially in a short field, becomes a pain for opposing defenses.
In those 13 red zone trips, Michigan has run 31 offensive plays: 25 runs and six passes. However, of those six passes, four have been touchdowns. Eight of the 25 runs have gone for touchdowns.
"You've got a big offensive line and they are working hard," Robinson said, trying to explain why Michigan has been so good. "You've got running backs running behind them, and they just give us a hole to get in there."
The runs, though, have not always been Robinson.
Halfback Fitzgerald Toussaint has run more than Robinson in the red zone, with 11 carries to Robinson's eight. In addition, Michael Shaw has received three carries, Vincent Smith two and Stephen Hopkins one.
The Hopkins carry was the closest Michigan came to losing its perfection. He fumbled on the goal line against Notre Dame, but the ball bounced right into Robinson's hands for a 1-yard touchdown run.
"We've done well," center David Molk said. "We just have a different, more powerful running game this year. I think it got put a lot on the coaches, and Coach Borges is calling plays really well."
Borges has been balanced with the runs he has called, even if Michigan has been overloading on the run inside the red zone. Hoke, when running through different personnel groups used in goal-line situations, listed at least six groupings Michigan doesn't use nearly as often outside of the red zone.
And the lack of turnovers has been critical. Robinson, while he has been inaccurate overall, has been good throwing the ball inside the 20. His touchdown pass to Drew Dileo against Eastern Michigan was one of the best throws he has made all year, hitting the receiver right over the middle, in stride.
Ball security and protection have also been emphasized often by Hoke and his staff. It all has led to Michigan's success, something that will be important as the Wolverines head into the Big Ten.
"We've just been focused on taking care of the ball," tight end Kevin Koger said. "The last couple years, we haven't had that great of success taking care of the ball. And we didn't on Saturday, but we're just looking to finish.
"And that's been an emphasis. And we've done a great job so far."
Michael Rothstein covers University of Michigan sports for WolverineNation. He can be reached at email@example.com or on Twitter @mikerothstein.