By Dave Goldberg

updated 4:32 p.m. ET Aug. 29, 2008

LaDainian Tomlinson supports Shawne Merriman’s decision to eschew surgery and play as long as he can with two torn ligaments in his left knee.

“How do you tell a warrior to sit down?” San Diego’s star running back said of his teammate. “That’s what he is, a warrior. He’s trained for this. It’s hard to tell a guy to sit down.”

That warrior’s code is preached continually by coaches: play through pain.

But too often, following the code has consequences far more serious than who wins the Super Bowl.

That’s why Merriman’s decision to ignore medical advice is a bad one — a risk to his career and his future. And if he doesn’t do something about it, the Chargers should.

It’s in stark contrast with the situation of another star pass rusher, the New York Giants’ Osi Umenyiora, who has been declared out for the season with a knee injury that may not be as severe.

There’s also a whiff of the warrior code in the death last week of Gene Upshaw, a Hall of Fame guard and union leader whose pancreatic cancer wasn’t diagnosed until three days before his died.

Merriman, whose 39½ sacks the last three seasons are the most of any NFL player, has tears in both the posterior cruciate and lateral collateral ligaments in his left knee, injured last December. He visited four different doctors, all of whom told him he needs surgery but left the decision up to him. As a “warrior,” he decided he would play. “If you give a football player a decision to play, you know, I’m going to play,” he said.

Bad move.

Umenyiora, who led the Giants with 13 sacks during their 2007 Super Bowl season, tore the lateral meniscus in his left knee on Aug. 23. He had surgery to repair it, almost surely ending his season.

From a medical standpoint, Umenyiora’s injury is considered less serious than Merriman’s, who eventually will have to undergo an operation that could need eight months of recovery. Umenyiora’s recovery time is estimated at four months. If the meniscus had been removed, he might have been ready to play in four weeks, meaning he would be available for most of the regular season.

But he and his team sacrificed the present for a healthier future.

Which brings us to Upshaw, who in the last couple of years of his life had been a target of retired players complaining they were denied long-term disability benefits from injuries incurred while playing. Some were players who had knee or hip replacements; others suffered from worse — dementia or Alzheimer’s from what many believe to be the effects of concussions.

He died on Aug. 20, just three days after he received his cancer diagnosis. That came only after his wife was finally able to convince him to go to a hospital. He had been complaining, according to close friends, that he had no energy.

There were signs even before that something was wrong.

People who saw him during the Hall of Fame induction weekend — Aug. 1-4 — noted that he had lost considerable weight — and among other things, his clothes looked too big for him. Upshaw brushed it off, saying he had been working out, as he did regularly.

Some bought it.

“He was going up and down all the time,” said Doug Allen, his former assistant at the union. “If he felt he was gaining weight, he’d work out as hard as he could to drop it.”

Obviously, it was more than workouts. But Upshaw’s mentality was typical of a Hall of Fame player who missed just one game in a career that ran from 1967-81. He played hurt and lived hurt, always trying to get back in the fray no matter what.

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