Kellen Clemens is an 11-year veteran who has a firm grasp of the Chargers offense and, as evidenced by his uneven preseason play and the fact he's thrown 10 regular-season passes in three years with the team, a limited ceiling.
Second-year pro Cardale Jones, acquired from Buffalo in August, has considerable physical gifts — size, strong arm, nimble feet — but might lack the touch and command of the offense to step in and be effective.
The Chargers open the 2017 season at Denver on Monday night with one of the league's best quarterbacks in Philip Rivers, the 35-year-old gunslinger who ranks 12th on football's all-time passing list with 45,833 yards in 13 years and has made 185 consecutive starts dating back to 2006.
You don't have to be hit with a lightning bolt to know the Chargers will need need Rivers' "Iron Man" streak to continue deep into December to have a chance to rebound from a 5-11 season and compete for a playoff spot,.
"The Chargers' ability to run the football and protect the quarterback is going to be critical this year," Rex Ryan, the former Buffalo Bills and New York Jets head coach who will be in the ESPN booth for Monday night's game, said on a conference call.
"I'm impressed by their starters, but offensively, I don't like their depth. If something ever happened to Philip Rivers … oh boy. You have to protect him. If the Chargers do that, there's no reason they can't make some noise in the conference and in the league."
The 6-foot-5, 228-pound Rivers has absorbed his fair share of hits in recent years — he was sacked a career-high 49 times for a loss of 311 yards in 2012 and at least 36 times in each of the past three seasons — but he's avoided a knock-out blow.
It also helps that Rivers, a traditional pocket passer who has averaged 28 carries in 11 years as a starter, is not a scrambling man.
"I've been reckless at times with the football, but I've never felt like I've played reckless from the standpoint of putting myself in position to take silly hits," Rivers said before Thursday's practice. "There is a fine line.
"If it's third-and-four and the game is on the line and I'm right there at the first-down marker, I'm probably gonna lay out for it. But there are times when you know to throw the ball away as opposed to gaining two yards or slide as opposed to trying to do something you can't do."
Effective blocking up front and the ability of a running back to pick up a blitzing linebacker or defensive back also would extend Rivers' shelf life.
A rebuilt line that features three new starters — left tackle Russell Okung, center Spencer Pulley and right guard Kenny Wiggins — will get its first test Monday against a Broncos defense that features outside linebacker Von Miller, who, with Houston's J.J. Watt, is considered one of the top two pass rushers in the NFL.
The 6-3, 237-pound Miller, a five-time Pro Bowl selection, can wreak havoc on an offense, using his speed, power, acceleration and hand techniques to average more than 12 sacks over six seasons.
"I know he gets a lot of attention for the sacks and the sack-fumbles, and rightfully so, but he's an every-down player," Rivers said. "He plays the run as good as any linebacker in the league. He's a guy who can change the game."
The Broncos move Miller from side to side to create favorable matchups "so at some point you have to block him one on one," Chargers offensive coordinator Ken Whisenhunt said. "You have to do everything you can to get help on him because he is so disruptive."
Okung and tackle Joe Barksdale will have their hands full with Miller. Running back Melvin Gordon, fullback Derek Watt and tight ends Antonio Gates and Hunter Henry might have to chip in to keep Miller away from Rivers.
"Everybody has a plan to slow down Von Miller, but it doesn't seem to work," Chargers coach Anthony Lynn said. "He's a great player."
- The Chargers will have different captains every week, with Lynn naming them in the locker room right before the game. “Everybody goes crazy, and we go out,” Lynn said. “It’s just the way I like it. I think certain guys step up each week. Some people evolve as leaders as the year goes on, and I think it’s best to reward guys and do it week by week.”
- Receiver Dontrelle Inman (groin), defensive end Jerry Attaochu (hamstring) and tight end Sean McGrath (knee) were limited participants in Thursday’s practice. All are expected to play Monday. Broncos cornerback Aquib Talib (Achilles tendon) and running back Jamaal Charles (knee) did not practice Thursday.
- The Chargers signed tight end Braedon Bowman, a South Alabama product who was recently waived by New Orleans, to their practice squad and waived linebacker Joseph Jones.