Undrafted rookie RB Austin Ekeler makes Chargers' initial 53-man roster

COSTA MESA, Calif. -- Here’s a player-by-player look at the Los Angeles Chargers' 53-man roster:

QUARTERBACK (2): Philip Rivers, Cardale Jones

As I reported earlier, Kellen Clemens is expected to be re-signed and return as the backup for Rivers for a fourth straight season, while Jones serves as a developmental prospect. When that happens, the Chargers will keep three quarterbacks on the active roster at the start of the regular season for the first time since 2013.

RUNNING BACK (4): Melvin Gordon, Branden Oliver, Austin Ekeler, FB: Derek Watt

Bruising running back Andre Williams played himself out of a spot on the final roster by averaging just 1.5 yards per carry during the preseason, while Ekeler did the opposite, averaging 5.8 yards per carry. The Chargers could make more moves here, bringing in another big back to spell Gordon.

TIGHT END (4): Antonio Gates, Hunter Henry, Sean Culkin, Sean McGrath

Gates and Henry combine to give the Chargers one of the best tight end duos in the NFL. Culkin was impressive as a blocker during the preseason, and if healthy, McGrath also provides some help in the run game.

WIDE RECEIVER (6): Keenan Allen, Travis Benjamin, Tyrell Williams, Dontrelle Inman, Geremy Davis, Mike Williams.

This group is perhaps the most talented position group on the team, giving the Chargers some time to get Mike Williams into game-playing shape after sitting out all of training camp with a back injury.

OFFENSIVE LINE (8): Russell Okung, Matt Slauson, Spencer Pulley, Kenny Wiggins, Joe Barksdale, Chris Hairston, Dan Feeney, Sam Tevi.

The Chargers are thin at offensive line and could look to make some moves on the waiver wire to shore up depth, particularly at interior offensive line. Center Max Tuerk is eligible to return off the suspended list in Week 5.

DEFENSIVE LINE (9): Joey Bosa, Corey Liuget, Brandon Mebane, Melvin Ingram, Darius Philon, Damion Square, Chris McCain, Jeremiah Attaochu, Isaac Rochell

Along with receiver, defensive line is one of the most talented position groups for the Chargers. Tenny Palepoi is eligible to come off the suspended list in Week 2, so the Chargers will have to make a roster move to add him.

LINEBACKERS (7): Korey Toomer, Jatavis Brown, Nigel Harris, Nick Dzubnar, James Onwualu, Kyle Emanuel, Denzel Perryman.

The Chargers could look to add depth at linebacker with Perryman out for an extended period of time. However, this group is more athletic than last year's.

SAFETIES (6): Jahleel Addae, Tre’ Boston, Adrian Phillips, Dexter McCoil, Desmond King, Rayshawn Jenkins

Comment: Dwight Lowery was the surprise cut of this group because of his dependability.

CORNERBACKS (4): Jason Verrett, Casey Hayward, Trevor Williams, Craig Mager

If healthy, Verrett and Hayward should be among the best cornerback duos in the NFL. But there's a pretty significant drop-off after those two. Brandon Flowers will be missed.

SPECIALISTS (3): (K) Younghoe Koo, (P) Drew Kaser, (LS) Mike Windt

In somewhat of a surprise move, the Chargers went with the undrafted rookie, Koo, over incumbent kicker Josh Lambo.