Jalen Richard says he is a perfectionist and his own harshest critic. So when the Raiders’ running back was asked what the biggest surprise has been in his rookie season, he didn’t hesitate.

“Me,” Richard said. He was dead serious.

“I surprised myself and now I have reached a point where, ‘OK, you can do this,’” Richard said. “I mean, I always had confidence in myself, but now I am at the top tier of the whole world that plays football. How do I measure up?”

At 5-foot-8, Richard has measured up just fine. He ran for a 75-yard touchdown on his first NFL carry, in the opener in New Orleans. He has 279 yards rushing and 123 receiving backing up starter Latavius Murray. And Richard has seized both the kick- and punt-returner jobs.

“It’s caught me off guard how well I am doing,” Richard said. “I was also surprised by how much confidence the team had in me so fast. I wasn’t even on the radar going into training camp.”

That he wasn’t. The Southern Mississippi alum came to the Raiders’ rookie camp in May on a tryout basis. The coaching staff liked his wiggle and burst and told him to stick around. And then he made the roster in September despite the fact that the Raiders had drafted DeAndre Washington, another 5-8 back who is very similar to Richard.

“A guy like Jalen, to step up and play as big as he has … (when) just to be here was a shock because it was a tryout,” head coach Jack Del Rio said. “Then, he comes into camp and he tears it up. The opening game, he makes huge plays to help us win, and he hasn’t looked back.”

Richard didn’t think the coaches were going to play him much when he made the roster.

“You drafted DeAndre, you have Taiwan (Jones), you’ve got Jamize (Olawale) that can play running back and you have” Murray, Richard said. “I didn’t think I was going to get an opportunity … and then I didn’t touch the ball in New Orleans until the fourth quarter.

“It just so happened I took it 75.”

That run was made possible by a vicious block by guard Kelechi Osemele, who still might be shoving the defender into the ground if the team hadn’t needed to fly home.

“Our linemen are enforcers,” Richard said. “Especially K.O. He is out there just trying to whoop up on anybody. I am very thankful for this line because they make me look good.”

Richard looks fast and has quickly gotten used to the speed of the NFL compared with college ball.

“When you settle down, the game still moves fast, but you’re able to react better,” he said. “It’s like muscle memory; I’m moving along with the speed of the game and things are clicking. People don’t get faster when they get to the league, they get smarter.

“Whether you’re a running back or a linebacker, see it, hit it. No hesitation.”

That’s true times 10 in the kick-return game, when opposing players are sprinting downfield with one target in mind: the returner.

Richard had a 47-yard punt return — the longest by a Raider since 2012 — on Oct. 2 in Baltimore and a 50-yard kickoff return against Kansas City two weeks later. The past two games, he has looked one block or one move away from breaking one for a touchdown.

“I am getting closer and closer,” Richard said. “I know I am due for one. Just steadily taking the coaching from (special-teams) coach (Brad) Seely, and going vertical first. Sometimes I have a bad habit of going lateral first, and then trying to get vertical.”

Either way, it has been better than what the Raiders have had. Oakland’s last punt return for a touchdown was Dec. 21, 2008, by Johnnie Lee Higgins, and the last kickoff return for a TD was Oct. 16, 2011, by Jacoby Ford.

“I hope I bust one really soon,” Richard said. “Monday night in Mexico would be the perfect time.”

Briefly: Del Rio said “nothing’s changed” regarding the status of suspended linebacker Aldon Smith, who was eligible to return to the team Thursday. Smith has applied to Commissioner Roger Goodell for reinstatement and Wednesday night tweeted a video of himself working out and saying, “I will not be defeated.” ... Defensive lineman Mario Edwards (hip) did not return to the team for Thursday’s practice.

Vic Tafur is a San Francisco Chronicle staff writer. Email: vtafur@sfchronicle.com Twitter: @VicTafur