SAN DIEGO (AP) Ken Whisenhunt returned to the San Diego Chargers and it's difficult telling who's happier: Whisenhunt or Philip Rivers?

Whisenhunt, the team's offensive coordinator in 2013, is back in the same role.

Rivers, who had one of his best seasons in `13, remains the quarterback of a team looking to rebound from a 4-12 record, its worst season since 2003.

More from FoxSports

''We really hit it off from that first year and we just picked it back up,'' Rivers said about his appreciation for Whisenhunt. ''He has a great feel for the offense.''

It's the same scheme Rivers and Whisenhunt collaborated on three years ago when it ranked the Chargers' offensive was No. 5 in the NFL. That helped the Chargers notch a road playoff win in coach Mike McCoy's first season.

But the Chargers have struggled since, missing the postseason and going 2-10 in the AFC West as they've been unable to find an offensive equilibrium after Whisenhunt left.

Whisenhunt's latest exit as a head coach came in Tennessee, where the Chargers play the Titans in opening the preseason on Saturday. Whisenhunt, a former Arizona Cardinals head coach, was dismissed when starting last season 1-6 after going 2-14 the previous year.

But it's this year Whisenhunt, 54, is focused on, with a belief the Charger can be among the NFL's most explosive teams.

Under Whisenhunt in `13, Rivers led the NFL with a career-high 69.5 completion rate, throwing for nearly 4,500 yards and 32 touchdowns, against just 11 interceptions.

''Any time you have a quarterback like Philip Rivers you can do that,'' Whisenhunt said. ''Because he can do so many things for you.''

Whisenhunt's mission also includes resurrecting the tepid running game. Despite drafting Heisman Trophy finalist Melvin Gordon in last year's first round, the Chargers ranked last in average rushing yards per play and 31st in rushing yards per game.

Gordon's rookie season was a disappointment as he failed to score a touchdown or rush for 100 yards in a game. The Chargers drafted fullback Derek Watt, Gordon's former Wisconsin teammate, and are hoping Whisenhunt can invigorate the ground attack.

Whisenhunt is encouraged Gordon will get on track.

''I've seen flashes,'' Whisenhunt said. ''But we still have to see what we've got. That is what the preseason games are for.''

If the Chargers have a running threat, it keeps Rivers, a 13-year pro, from harm's way. Numerous times Rivers faced third-and-long last season, which led to him being sacked 40 times and absorbing countless other hits.

''I think he'll do a heck of a job, along with the rest of the staff, of making us the balance attack we want to be,'' Rivers said.

It's clear Whisenhunt is where he wants to be in San Diego.

''It really wasn't hard to come back,'' he said. ''You kidding me? This is a great town.''

---

AP NFL website: www.pro32.ap.org and www.twitter.com/AP-NFL