When the Giants faced third-and-1 in the first quarter against the Carolina Panthers on Sunday, all 73,702 people at Bank of America Stadium in Charlotte had to know what was coming: In short-yardage situations, Giants coach Tom Coughlin loves nothing more than to see his 264-pound running back, Brandon Jacobs, trample opposing defenders.

But it didn’t work out as planned on Sunday. Jacobs took Eli Manning’s handoff, plunged into the middle of the line and got stopped cold. Carolina defensive tackle Maake Kemoeatu, who outweighs Jacobs by nearly 100 pounds, wouldn’t budge from the middle of the line, and safety Mike Minter came in to finish the tackle. The Giants had to punt, and Jacobs’s inability to pick up a yard when he needed it was the start of a rough day: The Giants gave him the ball with either one or two yards to go for a first down five times in Sunday’s 27–13 victory, and Carolina stopped him every time. He finished the day with just 16 yards on 10 carries.

Coughlin and Giants general manager Ernie Accorsi, who selected Jacobs out of Southern Illinois in the fourth round of last year’s draft, love him because his rare size, combined with an ability to burst through holes, makes him one of the best running backs in the league at picking up tough yardage. But opposing teams expect to see Jacobs in short-yardage situations and adjust their defense accordingly, as the Panthers did on Sunday when they kept Minter close to the line of scrimmage on third-and-1.

The week before, against the Dallas Cowboys, the Giants faced fourth-and-1 on the Dallas 24-yard line, and instead of sending in kicker Jay Feely for a 42-yard field goal, Coughlin decided to go for it with a handoff to Jacobs. But Jacobs never had a chance. Cowboys linebacker DeMarcus Ware made a beeline for him at the snap and drilled him three yards behind the line of scrimmage. The Giants’ failure to score on that drive was costly, as they went on to lose 23–20.

Ware looked like he knew what the Giants would do, and when opposing linebackers know which play is coming, it’s time to change the play calling. That’s exactly what the Giants did against Carolina. In the third quarter, after Carolina stuffed Jacobs on second-and-goal from the 2-yard line, Manning passed to wide receiver David Tyree in the middle of the end zone for a touchdown. That was the second time on Sunday that Manning threw a short touchdown pass on third down; he also found tight end Jeremy Shockey in the end zone for a two-yard touchdown pass in the first quarter. And on a fourth-and-1, after Jacobs had been stopped a yard short on third-and-2, Manning took the ball himself on a quarterback sneak to pick up the first down.

Jacobs’s failure in short yardage on Sunday — and the Giants’ success when Manning passed or kept the ball himself — doesn’t mean they should stop giving Jacobs the ball in those situations. He is too talented a runner not to carry in short yardage at least some of the time. The Giants need to pass often enough to keep defenses honest and prevent them from keeping their linebackers and safeties close to the line of scrimmage every time Jacobs is in the backfield on third-and-1.

The Giants’ current division of labor is clear: Tiki Barber gets the bulk of the work, but Jacobs does the heavy lifting. Jacobs has run the ball more often this year when the Giants have just one yard to go (25 times) than on first-and-10 (24 times). That play-calling is consistent with the relative skills of the Giants’ two backs: Jacobs has gained a first down on 31 of his 87 runs this year (36%), and he has eight touchdowns, but his longest run is just 16 yards. Barber doesn’t pick up first downs nearly as often, with 62 on 269 rushing attempts (23%), and just one touchdown. But Barber has more speed and elusiveness in the open field, and he has eight runs of 20 or more yards.

The Giants are lucky to have two backs with such complementary skills, but their opponents are so accustomed to the way they use Jacobs’s skills that they’re practically begging Big Blue to send him in the middle of the line. With three games to go and the playoffs on the line, the Giants will need to score plenty more — and as long as defenses are stacking the line to stop him, that will mean giving the ball to Jacobs less.

Mr. Smith is a writer for FootballOutsiders.com.