DALLAS (AP) — There has been little mystery with Alabama’s offense this season. The Crimson Tide have a 6-foot-3, 242-pound Heisman Trophy winner at tailback in Derrick Henry and the plan has been to swing that sledge hammer as many times as it takes to break the defense.

Michigan State is the next wall in the way.

The third-ranked Spartans face No. 2 Alabama on New Year’s Eve night in the College Football Playoff semifinal at the Cotton Bowl, and they are determined not to crack.

“As the game progresses, people wear down,” Michigan State co-defensive coordinator Harlon Barnett said Sunday. “You get tired of hitting that big back. Boom. Again. Here he comes again. Boom. Again and again and again. And so you have to have the mental toughness to be able to say, ‘Hold on. We’re going to hold up and we’re going to keep smacking him. Keep hitting him.’

“It’s a test of wills and his will has won out a lot of times this season.”

Michigan State linebackers Riley Bullough and Jon Reschke tweeted at Henry the night he won the Heisman how much they were looking forward to the challenge.

“can’t wait Derrick!!” was Reschke’s post to @KingHenry_2.

Henry set Southeastern Conference records this season with 1,986 yards rushing, 521 of those coming in the fourth quarter. The only quarter in which Henry has had more yards is the first (550), which is remarkable considering Henry sat out much if not all of the fourth quarter in a few of Alabama’s blowout games. His 6.1 yards per rush in the fourth is almost a full yard better than what he does in the third (5.2).

The old football saying for a running back such as Henry is that he gets stronger as the game progresses, but Tide quarterback Jake Coker has a little different perspective.

“He stays the same and everybody else changes,” Coker said.

So how does Michigan State plan to hammer Henry?

Replicating a 240-pound tailback in practice is nearly impossible. Michigan State (12-1) has used freshmen linebackers Kenny Willekes (6-3, 223) and T.J. Harrell (6-1, 209) on the scout team as ball carriers to give its defense the feel of tackling big target.

It’s not necessarily a matter of scheme. Alabama (12-1) has faced plenty of loaded boxes, with defenses crowding seven and eight players tight to the line of scrimmage.

“We understand what we’re facing and that he’s a fall-forward back,” Barnett said. “He’s not getting knocked back too many times.”

And when Henry gets into space, those long arms help keep defenders at bay.

“He’s definitely a stiff-arm runner,” Michigan State co-defensive coordinator Mike Tressel said. “With a guy that big you talk about taking out his legs, but sometimes he doesn’t let you get in there.”

Michigan State ranks ninth in the country in rushing yards allowed per game at 113.1 and 22nd in yards per carry at 3.55. The Spartans’ front seven is talented but not huge, with 275-pound nose tackle Malik McDowell and no starting linebackers listed above 230 pounds. The Spartans keep it simple defensively, play fundamentally sound and commit plenty of bodies to stopping the run.

“Well, we’re just going to keep bullets flying,” Tressel said. “That’s the way we play defense. We fill with just about all 11 people on a run play.”

The Spartans run defense was at its best in its biggest games, holding Iowa and Ohio State to a total of 138 yards on 53 carries.

“Michigan State’s whole defense is (built) around the premise to make negative plays,” said Alabama center Ryan Kelly, a second-team All-American. “And that’s what we want to eliminate. We had a lot of negative plays early in the season. Those are drive killers.”

Michigan State defensive tackle Joel Heath said the Spartans have to understand that just because they limit Henry once, twice or three times doesn’t mean Alabama will stop running its go-to plays.

“Alabama is great at running the inside zone, power all those different things,” Heath said. “If you don’t take it seriously every play, that’s when he makes a big break. I’ve seen great teams play great against him. But he’s consistent. If you’re not consistent with him, he’s going to make a big run, make a big play.”

Henry ran the ball 90 times (44 and 46) in Alabama’s last two games. He said there is no difference between carry 20 and 40.

“I think it’s really just all a mindset,” he said. “Let it affect you, then it’s going to affect you.”

With nearly a month since he last played, the Spartans figure Henry has had plenty of time to recharge.

“The thing about the workload is I wished we played him the week right after he had consecutive 40-carry games,” Tressel said. “But with the break that he’s had right now, he could carry the ball 80 times and he’d be fine.”

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Follow Ralph D. Russo at www.Twitter.com/ralphdrussoAP