ALAMEDA (AP) — Oakland coach Jack Del Rio defended his decision not to challenge a play that might have helped sustain a drive by the Raiders’ sputtering offense in the second quarter of Sunday’s loss to the Detroit Lions.

Of more concern to Del Rio is a three-game losing streak that has dropped his team to 4-6 and taken much of the shine off what began as a promising season.

From a defense that has become prone to allowing small gains to turn into backbreaking plays, to an offense that has scored just three touchdowns in its past 20 drives, the Raiders have looked more like a team than has missed the playoffs for 12 consecutive seasons than the team that got off to such a quick start this season.

“You are what you earn, right?” Del Rio said Monday. “We could talk about potential. Potential doesn’t win games. Production wins games. It’s a bottom-line business, it’s a production-based business. We expect to be better than we were.”

In two short weeks, Oakland has gone from being one of the surprise teams in the NFL to middle-of-the-pack territory — four games behind Denver in the AFC West and losing ground in the chase for the second wild-card spot.

Now the Raiders have to prepare for a road game in Tennessee where they’ve won just once in six tries.

“There are times where you hit these patches, and that’s life,” Raiders quarterback Derek Carr said following the loss to the Lions.

“That’s this league and that’s football. But there’s no doubt in our mind what we’re capable of. If there was, then there’d be a problem.”

Figuring out what’s ailing the Raiders could take some time.

After averaging more than 26 points through the first eight games, Oakland’s offense has managed just 27 points total in the past two games.

Wide receiver Amari Cooper — who is leading all rookies in catches and receiving yardage — has seemingly disappeared from the game plan in recent weeks. The fourth overall pick in the draft has only six receptions over the past two games and caught only one of the four thrown his way against Detroit.

“There were some opportunities with one-on-one coverage that quite frankly we didn’t take advantage of,” Del Rio said of Cooper. “We’ve got to do a better job of making sure our top playmakers are involved and coming out of that game I feel like we didn’t do a good enough job as a staff getting him involved.”

The Raiders also are uncertain whether center Rodney Hudson will be available this week. Hudson returned to the starting lineup against Detroit after sitting out the previous week with a sprained right ankle, but he left in the third quarter after appearing to aggravate the injury.

Defensively the Raiders have bigger issues to tackle — such as tackling.

Several times Oakland’s defense appeared to have the Lions stopped for short gains, only to see Detroit players breaking tackles, escaping coverage and sprinting downfield.

Two of the Lions’ longest gains of the day — a 36-yard catch by Calvin Johnson and an 18-yard reception by Joique Bell — came on third-down plays.

“Some of the easy football we need to keep easy,” Del Rio said. “Some of the plays that are not really difficult to defend, we’ve got to get those plays defended better now. We’re 10 weeks into this thing. You can’t play great defense if you have giveaways, if you have gifts that you give your opponent. It’s imperative that we close that down, that we get that rectified ASAP.”

As for the play to wide receiver Michael Crabtree in the second quarter, Del Rio stood firm on his decision not to throw the red challenge flag. Crabtree caught the pass from Derek Carr, got both feet inbounds then took three steps out before the ball came out of his hand near the turf.

The pass was ruled incomplete on the field, but former NFL official Mike Carey said during the TV broadcast that the play should have been overturned.

“I think we could do the 100 people in the bar test and there’d be 99 if not 100 percent (who) would say that’s a catch,” Del Rio said. “Frustrating, but that’s what it is.”

Notes: Del Rio said he expects to have TE Lee Smith back at practice this week. Smith did not play because of a wrist injury. TV announcers said that Smith had surgery on his right wrist last week, but the Raiders made no official announcement. ... Oakland’s offensive line gathered to pass out turkeys to families in need Monday night.