During Raiders running back Latavius Murray’s breakout game on Nov. 20, 2014, he gashed the Chiefs defense for a 90-yard touchdown run.

One of the prime victims on that play was Eric Berry. Murray galloped past, and Berry never narrowed the gap between them to fewer than five yards. It was a poor performance by one of the best safeties in the game.

But Berry’s struggles in that contest seem more than understandable in retrospect. He was playing with a cancerous tumor in his chest, which would end his season after that game and require six phases of chemotherapy.

Eric Berry

Just 247 days after the Chiefs announced Berry had cancer, he was back practicing at training camp.

"He’s done a tremendous job with what he has been through," Chiefs defensive coordinator Bob Sutton said. “To come back this soon on the field is an incredible story.”

Berry’s comeback is not only an incredible story, but his presence also will help a Chiefs defense that will be without two of its best defensive players during the first several weeks of the season.

Dontari Poe

Dontari Poe is the heart of the Chiefs defense. The 6-3, 346-pound nose tackle collapses the pocket, allowing edge rushers Justin Houston and Tamba Hali to attack the edge and get to the quarterback.

But the four-year player underwent a microdiscectomy on July 15 to remove a portion of a herniated disc that was impinging on a nerve in his back. (Chiefs LB Dee Ford underwent the same procedure in college.)

Even with intense rehab, it still will take a physical marvel like Poe about four to six weeks post-operatively until he can lift weights and three months post-op before he can play football.

Dontari Poe

That means Poe -- an excellent pass rusher and tough run defender -- is likely out until around Week 6.

“That’s a huge loss. Dontari’s made the Pro Bowl three years in a row,” Hali said. “He’s a sack guy. You can’t leave him one-on-one. He’s very athletic. He demands for two men to block him every play.”

Few can match Poe’s combination of power and speed.

During the 2012 NFL Combine, Poe benched 225 pounds a staggering 44 times -- a Combine-high that year -- while running the 40 in 4.98 seconds. That speed explains how a 346-pound nose tackle runs down running backs on screen passes -- as he did to RB Ryan Mathews.

Poe also has demonstrated incredible stamina. Heading into Week 14 of the 2013 season, for example, he had been in the lineup for 95 percent of Kansas City’s defensive plays, which amounted to 804 snaps and was 85 more than any other NFL defensive tackle.

“He doesn’t like to come off the field,” Sutton said. “That is an usual thing for the big guys like that.”

Poe’s absence represents a major void. Traditional 3-4 ends Jaye Howard and Mike DeVito, who missed last season after tearing his Achilles tendon in Week 1, may slide over to replace Poe.

“I like playing nose. It’s definitely different (than playing) a three technique,” DeVito said. “It’s funny. It’s what -- only a couple yards over -- but it’s really a different world down there. But I am excited and I am ready to go if they want me to do it.”

Sean Smith

The Chiefs' best cornerback from the 2014 season, Sean Smith, will miss the first three games of the 2015 season after pleading guilty to an April DUI charge.

Sean Smith

One of the biggest cornerbacks in the NFL at 6-3, 218 pounds, Smith has the perfect body type for the aggressive man coverage Sutton employs.

Much of the burden to replace Smith will fall on rookie Marcus Peters, who the Chiefs drafted with the 18th pick in the 2015 NFL Draft and was seen receiving tips on outside combination routes from Smith during practice.

Peters was considered by many to be the best cornerback in the draft, but a variety of off-the-field issues -- which ultimately resulted in him getting kicked off the University of Washington football team -- caused him to slide in the draft.

For what it’s worth, the 6-0, 197-pound rookie has played well early in training camp, even intercepting four passes during an Aug. 3 practice.

“Marcus did some really nice things. He had a couple of nice plays,” Chiefs coach Andy Reid said. “Now it’s important that he’s consistent.”

Eric Berry

Berry’s speedy recovery could help replace Smith as well, potentially allowing Ron Parker to shift from safety to cornerback.

Instead of receiving chemotherapy in the traditional way through a port or a center catheter that goes to a major vein in his heart, Berry opted to have IVs every time he underwent chemotherapy so that he could exercise.

"Even when he was going through chemo, he was always constantly working out," Houston said. "He is built different. ... For a guy to still be going through chemo and not stopping working out and constantly always working, you have to be real strong-minded."

Chiefs Fans

Berry went from not leaving his bed to being unable to perform five push-ups ... to squatting 375 pounds five times and benching 275 five times right before training camp.

He recorded those numbers in the weight room as he was being evaluated for a return to football. Berry underwent four extensive tests over six days. Doctors monitored his strength, hormone levels, bone density, lung and cardiac capacity.

“He sailed through every test that we gave him,” said Chiefs head athletic trainer Rick Burkholder.

Having passed the health tests, Berry is currently practicing with the second team behind free safety Husain Abdullah. Whether Berry can regain the form that sent him to three Pro Bowls remains to be seen.

Regardless, his return to the field represents an uplifting story for a defense sorely in need of one.

Related Story: David Wilson ... One Year After NFL Retirement, One Year Before Rio Olympics

-- Follow Jeff Fedotin on Twitter @JFedotin.

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