OAKLAND — Not until late in the third quarter Saturday did Raiders fans at the Coliseum reach full roar and come out of their seats. A few went out of their minds.

This spasm of passion was a response to a single play by the backup quarterback’s backup — in an exhibition game.

Terrelle Pryor, entering his second NFL season, is third string on Oakland’s depth chart, nowhere near being a legitimate threat to the job security of backup Matt Leinart, much less starter Carson Palmer.

Pryor is a developmental project, and the development is still very much in its early stages. The Ohio State product is, at best, years away from a finished product.

But fans bothering to attend the Raiders’ 31-20 win over Detroit are yearning for a revival. They’d sat patiently, witnessing mostly ordinary activity. Irritating penalties (addictions are hard to break) and ghastly displays on special teams (an unwanted new habit) were framed by spurts of offensive production and defensive muscle.

The Raiders and their fans, 41,104 in attendance, needed something, anything, to stir the senses. Pryor delivered.

On a third-and-6 from Oakland’s 27, with 2:11 remaining in the third quarter, Pryor dropped back to pass, spotted a huge hole and went whoosh. He tucked the ball under his arm, sprinted through the space, racing past defenders, untouched until Detroit cornerback Justin Miller snagged him 59 yards later.

“I felt myself flying, going past everyone,” Pryor said.

Though Pryor is 6-foot-5 and 230 pounds, he moved like a sleek running back. And, suddenly, it was as if the building awakened. For the first time in the game, the Coliseum shook with the energy of momentary delirium.

Two plays later, Pryor shook off a tackle and strolled in for a 17-yard touchdown, giving the Raiders a lead (17-13) they would not relinquish in giving first-year coach Dennis Allen his first win of any kind.

“We talk about creating habits, and you’re either creating good habits or bad habits,” Allen said. “And today we created a good habit.”

Pryor took the field for five possessions, three of which concluded with touchdowns, a display of offensive efficiency not yet seen under Palmer. Pryor’s most notable blemish, a pass intended for wide receiver Rod Streater that was intercepted by Lions cornerback Alphonso Smith, was nullified when Smith was flagged for illegal use of hands.

Interceptions happen. All passers are victimized, and Pryor, certainly for now, is more susceptible than most. It’s part of the package that is Tantalizing Terrelle.

Given another chance, Pryor two plays later lofted a 39-yard pass that rookie wideout Juron Criner plucked away from Smith, who was flagged for interference, in the end zone for a touchdown with 11:44 remaining.

“That was a bad ball,” Pryor acknowledged. “Criner just made a great play.”

Pryor made good on the next possession, floating yet another pass, more accurate and with perfect timing, that Criner grabbed before dashing in for a 76-yard touchdown that cracked open what for most of the evening was a close, low-wattage game.

The potential for offensive fireworks is why the Raiders nabbed Pryor with a third-round pick in last summer’s supplemental draft. He’s an inferior passer, to be sure, but he’s wrapped inside a spectacular athlete and marvelous runner. He’s flawed but rich with the promise of thrills, the most electrifying Raider not named Darren McFadden.

That’s why Pryor is so intriguing and why his work was the highlight of the evening — in contrast to his last appearance here, a dismal showing in Oakland’s exhibition opener against Dallas, after which a Pryor blamed himself for just about everything except the national unemployment rate.

What changed? Pryor pointed to several factors, including an increased practice workload, tighter direction from offensive coaches and the constant tutelage of Palmer.

“I’m just happy for him,” said Palmer, who’s in his 10th NFL season. “Proud of him.”

“He’s like a big brother,” Pryor said.

Palmer is the key to this offense achieving its potential. He knows the league, has the arm and brings the intangibles. Pryor is a willing student. That he completed 3 of 5 passes for 137 yards and two touchdowns — and ran five times for 90 more yards — suggests he is learning.

Contact Monte Poole at mpoole@bayareanewsgroup.com. Follow him at Twitter.com/1montepoole.