Tyrell Williams is kind of like that 1996 Pontiac Grand Prix he bought for $900 as a college freshman, a green sedan with 274,000 miles on it that he still drives when he's home in Oregon — modest, unassuming, often overlooked.

"It's a good car, a reliable car," the Chargers wide receiver said with a grin during last week's minicamp. "And it's still rolling."

Just like its owner, despite the roadblocks that nearly thwarted his career.

Williams didn't receive any major college scholarship offers after starring in three sports at tiny Cascade High in Turner, Ore., so he went to Western Oregon, an obscure Division II school in Monmouth, to play football.

He did not get picked in the 2015 NFL draft after a solid college career in which he caught 165 passes for 2,792 yards and 21 touchdowns, so Williams signed as a free agent with the Chargers with little chance of making the team.

Though he earned a 53-man roster spot out of training camp in 2015, Williams was relegated to special teams — as a "gunner" on the punt team — in the few games he played in, and he spent two months on the practice squad.

Then his career trajectory shot upward on one play in the season finale, an 80-yard touchdown catch early in the fourth quarter of a 27-20 loss to the eventual Super Bowl champion Denver Broncos in Sports Authority Field.

An injury pushed Williams into the playing rotation at receiver, but the heavily favored Broncos, with their stout defense, were smothering the Chargers' passing game with a cover-four zone.

"We needed a four-beater, and we didn't have it in the game plan," Chargers receivers coach Nick Sirianni said. "So we drew up a 'scissors' play for Tyrell."

Williams lined up in the slot to the right of tight end John Phillips, who ran a quick out pattern toward the right sideline. Philip Rivers, from his 20-yard line, dropped back after a play-action fake.

Williams broke off the line, gave Aquib Talib a head nod as if he was breaking right, and sprinted past the star defensive back and toward the post. Williams was wide open when he caught the pass at the Denver 45 and continued untouched to the end zone to give the Chargers a 20-17 lead.

It was Williams' first NFL catch, the longest first catch by a player in Chargers franchise history, and a career-altering catch for the receiver.

"It definitely catapulted me," Williams, 25, said. "Just to be out there, to get the feel of the game, going through the routes and blocking, and then to get that play drawn up on the sidelines and to run it ... I mean, there's no better way to get your first catch. It let me know I could play. I got the feel of it. I wanted more."

Williams entered training camp in 2016 as the team's third or fourth receiver. Then veteran receiver Stevie Johnson suffered a season-ending knee injury in early August, and star receiver Keenan Allen suffered a season-ending knee injury in the opener against Kansas City.

Thrust into a starting role, the 6-foot-4, 205-pound Williams had a breakout season, leading the Chargers with 69 receptions for 1,059 yards and seven touchdowns. He was targeted a team-high 119 times.

"Injuries gave me the opportunity," Williams said. "I wanted to make the most of it."

Known for his ability to turn short passes into big gains, Williams was fifth in the NFL in receptions of more than 25 yards, with 13. Roughly 70 percent of his catches went for first downs.

"He caught so many five-yard shallow routes, where all Philip had to do was flip him the ball, and turned them into big plays," Sirianni said.

"You get this guy running with the football ... he's big and he's strong and he's fast. He was able to stretch the defense and get behind guys on deep crossing routes."

Looking at Williams' statistics, his ability and the impact he had on a 5-11 team last season, it's natural to wonder: How did this guy not get drafted?

"That's a good question," said Arne Ferguson, Western Oregon coach. "We thought he was very talented. He had size and speed. He was double covered his whole senior year and still had an amazing season. Everybody who came through here liked him."

Not many scouts came through, though, and for those who did, it was tough to evaluate Williams against lesser competition. Williams also was slowed by a shoulder injury that required surgery after his senior season.

Williams shined at his predraft pro day at Oregon State, where he caught passes from then-Beavers quarterback and now-Rams backup Sean Mannion. But his name was not called in the draft.

"I think it was because I was a small-school Division II guy," Williams said. "I never really found out why I wasn't drafted. I used it as motivation."

The Chargers were the only team to call Williams after the draft, so Williams signed and headed for San Diego with one goal: "To do something to make the coaches notice me every single day," he said.

That meant working hard in the weight room, learning the playbook, catching everything thrown his way in practice and excelling in preseason games on offense and special teams.

"I just wanted an opportunity to keep playing football," Williams said.

Williams made the most of his chance, emerging as Rivers' favorite target last season, but that doesn't guarantee him a starting job — or even a major role — when the Chargers begin training camp in Costa Mesa in late July and begin play come September.

Allen is back from his injury, Dontrelle Inman (58 catches, 810 yards, four touchdowns) and speedy wideout Travis Benjamin (47 catches, 677 yards, four touchdowns) are coming off solid seasons, and the Chargers used the seventh pick in the draft on star wide receiver Mike Williams of Clemson.

The Chargers also have two standout tight ends in Antonio Gates and Hunter Henry, and Melvin Gordon is a pass-catching threat coming out of the backfield.

Tyrell Williams looks at the abundance of receivers and the addition of Mike Williams as a boon to the Chargers, not a threat to his job.

"I was excited to bring in another guy who can help our offense," Williams said. "There's no bad blood between any of us. We're all going out and trying to win games. We have so many weapons, you can't just key on one guy. I think our offense is going to be one of the best in the league."