The Chargers suffered a significant blow when Antonio Gates was suspended for the first four games of the regular season after testing positive for PEDs. But even though Gates is one of San Diego's best players, he's not necessarily one of its most indispensable.
Mike McCoy has several practical options for replacing Gates' production, such as plugging in the smooth and speedy Ladarius Green and using more four-receiver sets (meaning more playing time for emerging star Dontrelle Inman).
This got us thinking: Who are San Diego's most indispensable players? After research and review, these six top the list.
QB Philip Rivers
This list would be a mockery without No. 17 atop of it. Not only could the Chargers not challenge for a playoff spot without Rivers, they would be fortunate to win a single game. That is especially true heading into the 2015 season, as McCoy's offense is designed around Rivers' ability to get to the line quickly, survey the defense and adjust his troops on the fly.
Also, Rivers' ability to move around in the pocket and get rid of the ball quickly makes life much easier for his offensive linemen. His accuracy is unmatched, as well; he has completed better than 64 percent of his passes in six of the last seven seasons.
McCoy has called Rivers "one of the best in the business."
RB Melvin Gordon
Gordon is on this list not for anything he's done -- at least not on the NFL level -- but what what San Diego's offense did without him. Last season, San Diego ranked No. 30 in rushing yards per game (85.4) and No. 31 in yards per carry (3.4).
Gordon boasts big-play ability, averaging 7.6 ypc over the last two seasons. He also has the power, agility and balance to force defenses to bring an eighth defender down into the box.
With Gordon toting the rock, newcomer Orlando Franklin opening up running lanes and Danny Woodhead returning as the change-of-pace back, San Diego's running game should get back to a championship level.
"He's an exciting, electric football player," said GM Tom Telesco of Gordon. "We need more guys like that."
OT King Dunlap
Left tackle is a premium position on every NFL team, but that is especially true in San Diego. That's because beyond Dunlap, the Chargers do not have anyone capable of protecting Rivers' blindside.
It's been quite a rise for Dunlap, 29, who originally joined the Chargers on a modest two-year deal with the expectation he would be the team's swing tackle. Instead, he has been entrenched as the starting left tackle over the last two seasons. He was at his best in 2014, starting all 16 games for the first time in his career and allowing just 3.5 sacks.
His efforts did not go unnoticed. He was named the team's Lineman of the Year and signed to a new four-year, $28 million deal.
"King has been top notch the last few years for us at left tackle," Rivers said. "[The new contract is] very well-deserved for him personally and a huge signing for our team."
DE Corey Liuget
Here we have another member of the "new contract club." Liuget signed a five-year, $58.5 million extension earlier this offseason after leading the team with 4.5 sacks and 11 tackles for loss.
"Corey is hard-work personified," McCoy said. "He will do whatever it takes to get better and help the team. And he's still improving. There's no limit to how good he can be."
Liuget has long been an SDBR favorite. For the last three years he has been touted here as the best player on San Diego's defense. And in all of our stories previewing the 2015 offseason, we insisted Liuget should be in line for a new deal ahead of Eric Weddle, a sentiment Telesco ultimately agreed with. But in all honestly, his inclusion on this list has as much to do with the talent around him -- or lack thereof -- as it does with Liuget himself.
The defensive line is San Diego's weak link. There are no blue-chip players other than Liuget. There are some players who've flashed at times, like Kendall Reyes and Ricardo Mathews, and some interesting prospects such as Ryan Carrethers and Darius Philon. But the drop-off in talent between Liuget and the next best defensive lineman is almost as steep as the drop between Rivers and Kellen Clemens.
OLB Melvin Ingram
It scares me to put Ingram on this list of "most indispensable players," since he has been "dispensed" for 19 games over the last two seasons. But he raised the bar in 2014, recording four sacks and two forced fumbles in just nine games. He is expected to be a 10-sack player if he can stay healthy in 2015.
The Chargers are counting on Ingram to do exactly that after parting ways with Jarret Johnson and Dwight Freeney. Suddenly, Ingram is the veteran leader of a group that also includes recent draft picks Jeremiah Attaochu, Tourek Williams and Kyle Emanuel.
Ingram has put in an incredible amount of work this offseason to prepare for the increased workload. He is down to 246 pounds, 20 pounds lighter than last season, which should make him more explosive coming off the edge.
"Being at 260 or 265, 266, wasn't working, really. I felt quick but I kept getting injured. ... The lighter you are, the less stress it is on your body, the less stress it is on your knees, your hips, your joints or your ankles, your toes -- everything," said Ingram, according to UT San Diego.
CB Jason Verrett
Someone from the secondary belongs on this list. Strong arguments could be made for Eric Weddle and Brandon Flowers, but I'm going with Verrett. And I'm going with Verrett largely because of the reaction I had last season when the Chargers placed him on injured-reserve; the minute that transaction took place, I dismissed the Chargers as Super Bowl contenders.
Verrett completely changes the complexion of the defense. With him on the field, quarterbacks can no longer throw away from Flowers with impunity. Verrett has the speed, quickness and anticipation to hang with any receiver in the game and make plays on the ball.
Verrett may move inside to cover slot receivers on third downs, a luxury the Chargers can now afford with Craig Mager and Patrick Robinson added to the cornerback mix. That should provide a significant boost for John Pagano's unit, which was the league's No. 25 third-down defense in 2014.
"We've got a lot of guys that can play a lot of different parts in this defense," Flowers told ESPN.com earlier this week. "And it can create havoc for offenses. I would love to just have Jason Verrett out with me this whole season because he's electric. You need a guy like that on the field. And nothing is going to get him more prepared and better as a player than experience."
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Michael Lombardo has covered the San Diego Chargers since 2003. He spent 12 years covering the team for Scout.com and has been published by the NFL Network, Fox Sports and MySpace Sports. In addition to being publisher of SDBoltReport.com, he works as the Senior NFL Reporter for Footballinsiders.com. You can see more of his updates by following him on twitter @NFLinsider_Mike.