A football team is a brotherhood. That goes for the 53 men on the roster when the season starts, not necessarily the other 37 players who are at training camp currently wearing jerseys.

But Jalen Richard, an undrafted running back out of Southern Mississippi, has found an ally, someone who comes up to him after a nice run at practice and congratulates him. What makes it especially unusual is that it’s not another running back but starting tight end Lee Smith.

“It’s been really cool,” Richard said. “Lee talks to me all the time, tells me I am doing a good job and to keep pushing.”

The 5-foot-8 Richard and 6-foot-6 Smith are both from the South, Smith growing up in Powell, Tenn. Richard said teammates were giving them a hard time about their accents and they formed a bond.

“It is kind of crazy,” Richard said, smiling. “We were messing around one day, and then he pulled me over for a real conversation.”

Smith offered Richard tips on how to be a pro, mixed in with stories about life on his ranch with his wife and kids.

“All the players know everybody’s not going to be able to be here the whole time,” Richard said. “So some people tend not to build relationships because of that. But then you have the ones that don’t worry about that at all, and treat you like you’re going to be here forever. Lee is one of those guys.”

Here’s a secret: Smith, a sixth-year veteran, wasn’t drawn to Richard because of his accent.

The tight end, after practice one day last week, pointed to the rookie catching tennis balls from a machine.

“There are a lot of rookies in there right now who have never played a down in this league taking a shower,” Smith said. “And this kid’s out here working. You know what I mean? You kind of gravitate toward certain kids, you respect them and their work ethic. He’s special.”

During practices, Richard has shown some wiggle and a nose for the hole, and has been lining up with the third-team offense, behind starter Latavius Murray and fifth-round pick DeAndre Washington.

Richard has even gotten to line up with starting quarterback Derek Carr a few times. It’s a long way from coming to the team’s rookie camp in May on a tryout, and getting a contract after it.

“I am just trying to take advantage of every opportunity I am given, and hopefully more opportunities come,” Richard said. “

Raiders head coach Jack Del Rio has been impressed.

“We have a lot of reps in camp. A lot of different guys get opportunities. Yeah, I would say he’s done a nice job with the looks he’s gotten so far.”

Richard ran for 1,098 yards and 14 touchdowns on 185 carries (5.9 per carry) his senior year, and also had 284 yards and two touchdowns receiving. He thinks catching the ball is his strength.

Richard didn’t think he did well in the Raiders’ offseason workouts, “because I wasn’t comfortable with the offense, but I am now.” He also did well for himself returning kickoffs Saturday, which improves his chances of making the roster.

Richard, at 207 pounds, is three pounds heavier than Washington. Otherwise the rookies are carbon copies of each other. Both say being a smaller player works in their favor against defenses.

“It’s definitely an advantage if you know how to use it,” Richard said. “It’s crazy how identical DeAndre and I are as far as size, weight and skill set. We use our size to our advantage, because guys can’t really see us behind the (offensive) line. We are very precise in our cuts and we have great vision.”

While Washington was drafted, Richard wasn’t, and only two teams offered him tryouts (the Raiders and Bucs) because of his size.

“I am just happy for the opportunity,” Richard said. “It’s definitely cool to be out here now with Derek Carr and Khalil Mack.”

And it’s nerve-racking as well.

“It’s just football all over again, that’s what I tell myself to calm myself down before practice,” Richard said. “I tell myself, ‘I’ve been doing this since I was 5 years old.’”

And if that doesn’t do the trick, Richard will hear a deep voice yelling encouragement after a play.

“I really appreciate Lee’s words,” Richard said. “He’s like my big brother now.”

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