It began, one could argue, in the early hours of Sept. 1, when the Raiders traded edge rusher Khalil Mack to the Bears.

Until then, there had been optimism that with a returning core and an intriguing offense the Raiders could recapture some of their success under returning head coach Jon Gruden.

Halfway through, the Raiders are 1-7, their lone victory having come against a Cleveland team that has since fired its head coach.

Amari Cooper, like Mack, was traded. Defensive captains Bruce Irvin and Derrick Johnson were cut. Cornerback Dominique Rodgers-Cromartie retired.

And as the Raiders staff a succession of rookies and free-agent signings, the implication of their first eight games is that their focus lies not in the remainder of this season, but beyond.

OFFENSIVE MVP: RB Marshawn Lynch

At 32, Lynch ran through the first month of the season like a much younger man, shedding tackles, showing a burst that wasn’t always evident last season and compiling 300 rushing yards in the first four games. That’s why it surprised the Raiders when, after their Week 6 loss to Seattle in London, Lynch was revealed to have a groin injury that will keep him out until at least Week 16 — if he comes back at all.

That Lynch is mentioned here reflects the rest of an offense that ranks 19th in yards per game and 28th in scoring. Lynch’s determined 10-yard touchdown run on the Raiders’ first drive of the season offered promise that hasn’t come to fruition.

Now the question is whether he has played his last game in a Raiders uniform.

MOST DISAPPOINTING, Offense: WR Amari Cooper

This is not entirely on Cooper. In February, Gruden said he intended to make Cooper, a two-time Pro Bowl receiver, a focal point of the Raiders’ passing offense. That did not come to pass.

In six games, before he was traded to Dallas on Oct. 22, Cooper had just 22 catches for 280 yards and one touchdown; 18 of those receptions and 244 of those yards came in two games (Weeks 2 and 4). In his other four games, he was targeted 10 times for four catches and 36 yards.

There wasn’t consensus on why Cooper disappeared at times. But when the Raiders acquired a first-round draft pick in exchange for him, it seemed like a favorable price.

DEFENSIVE MVP: DT Maurice Hurst

It’s telling that a rookie defensive tackle and fifth-round draft pick has been one of the few bright spots on the Raiders’ defense this season.

Hurst has played the most snaps of anybody on the line (61 percent). He leads that group with 15 solo tackles, has defended three passes and leads the Raiders’ current roster in sacks — with two. The Raiders are last in the NFL in sacks, have forced the second-fewest turnovers and rank dead last against the run. Hurst has experienced growing pains but appears to be a player who will figure into the Raiders’ plans.

MOST DISAPPOINTING, Defense: LB Bruce Irvin

There are quite a few options here.

But we’ll go with Irvin, whom the Raiders owed $8.25 million this season and who totaled six tackles and three sacks in eight games before he was waived last weekend.

Irvin was placed in a pass-rushing role and talked before the season about reaching double-digit sacks for the first time. But after Mack was traded, Irvin clearly was not as effective as the primary edge rusher.

His opportunities decreased in the weeks before he was released (nine snaps against the 49ers). A team co-captain, he talked loudly in the locker room after the Raiders’ loss in London about going home and making babies.

BEST DRAFT PICKS: Hurst/T Kolton Miller

We’ve covered Hurst. Miller, who came into camp with the expectations of being a first-round pick in April, also has shown promise — albeit tempered in recent weeks by a nagging knee injury.

Miller, who stepped in immediately at left tackle with Donald Penn out, has started all eight games and was solid early. His movement has been hampered by the knee injury, which led to his early exit from the loss to the 49ers. It remains to be seen whether the Raiders, given their record, will continue sending out their first-round pick to play at less than full strength.

WORST DRAFT PICK: P Johnny Townsend

Gruden recently recalled going through growing pains with Shane Lechler, the last punter he drafted in Oakland, who “used to punt the ball out of the Black Hole.” OK, but Townsend has had arguably the opposite issue.

The Raiders’ fifth-round pick ranks 32nd in average distance among punters with at least 15 attempts and 28th in net average. Directional punting was a strength for him in college, but Townsend has pinned opponents inside their 20-yard line on just six of 32 punts — also a reflection of the Raiders’ struggling offense.

BEST FREE-AGENT SIGNING: CB Daryl Worley

The cornerback gets this nod despite being suspended for the first four games of the season.

Worley, whom the Raiders signed in April after he was released by the Eagles following an arrest, slid into a starting role almost immediately upon returning.

Despite playing only four games, Worley ranks third among Oakland corners in tackles (19) and has four passes defensed and one of the team’s four interceptions. Coaches talk about him as if he has been in the league for some time, though he is just 23 years old.

WORST FREE AGENT SIGNING: CB Rashaan Melvin

The Raiders gave Melvin a one-year deal worth more than $5 million to prove he can be a No. 1 cornerback. He started the first five games, had their first interception and is tied for the team lead with seven passes defensed.

But he fell out of the lineup in Week 6, publicly expressed his frustration with techniques the Raiders teach and has been inactive the last two games. That, of course, is the Raiders’ decision. But the investment isn’t yielding any returns while Melvin isn’t playing.

BEST PLAY

With the Raiders trailing Cleveland 28-14 in the third quarter in Week 4, Hurst forced a fumble by quarterback Baker Mayfield that was recovered by the Raiders and sparked a 20-0 run, helping force overtime in their only victory of the season.

WORST PLAY

Again, multiple choices here, but nothing rubbed salt in the wound like seeing Miami receiver Albert Wilson take a jet sweep 74 yards for a touchdown with such ease that he high-fived teammate Jakeem Grant at the 15-yard line on his way to the end zone.

BEST QUOTE

“It’s hard to find a great one. It’s hard to find a good one.” — Gruden on pass rushers, less than three weeks after the Raiders traded Mack to Chicago.

Matt Kawahara is a San Francisco Chronicle staff writer. Email: mkawahara@sfchronicle.com Twitter: @matthewkawahara