The bigger the running back, the bigger the target.

That goes for defensive players, as well as fans, when it comes to the Raiders’ Latavius Murray.

Murray ran for 1,066 yards — sixth in the NFL — last season, his first as a starter, and made the Pro Bowl. But the experts on social media say the 6-foot-3 back ran too high, doesn’t have good vision … some even question his toughness, though he played all 16 games despite suffering two concussions.

Murray should just log on to Twitter before games to get motivated.

“I don’t go looking for it, or digging, and I don’t care … but yeah, I’ve seen plenty,” Murray said. “That kind of stuff doesn’t faze me. I’ve had to prove myself all my life.”

And here’s the thing: If you don’t think Murray had a good season last year, Murray actually agrees with you. As far as he is concerned, he had too many “zero games,” and his Pro Bowl jersey might as well have had “Alternate Selection” stitched in place of his name.

“Or maybe an asterisk,” Murray said, laughing. “I mean, it was a lot of fun. Being there with the best of the best, and having my family come out and experience that with me. I had never been to Hawaii, and they hadn’t either, so that was the coolest thing.

“But now, I want to go back on my own terms. I know I could have played better and forced myself in there without any doubt.”

Murray was a sixth-round draft pick from Central Florida in 2013, and he has shown that he is quicker than scouts thought. But entering his contract year, he still sees himself as a sixth-round pick.

“Every single day, every time I step on the field, I have to prove myself. There are going to be new backs that come in every year and I have a spot to keep. I am going to do what I have to do to make sure I am the guy on the field.

“I want to stay like that. I don’t want to ever get comfortable.”

The new backs this season are fifth-round pick DeAndre Washington and undrafted free agent Jalen Richard, a year after Roy Helu Jr. arrived injured and simply didn’t get right. Murray wound up with 266 carries last season.

Quarterback Derek Carr was second on the team with 33 carries.

“There was never a point where it diminished the way I played,” Murray said. “But if these guys are going to come in and give me breath, I am all for it.”

Murray will lose some snaps to Washington in passing situations, but his overall workload should be close to last season’s, as head coach Jack Del Rio wants to run the ball more.

“I want to have more rushes,” Del Rio said. “I don’t want him to have less. If anything, maybe a little more, but I want him to be more productive. We’re working on becoming a team that’s capable of running the ball well. We never really, truly established that last year.”

Murray very easily could become the first Raiders running back to top 1,000 yards in back-to-back seasons since Hall of Famer Marcus Allen in 1984 and ’85.

“I think he can be one of the best in the league,” Carr said. “He has the size, obviously. You see him walking around and you think, that guy plays running back?

“First day I got here, I was like, ‘There’s no way that guy is a running back.’ But sure enough, he was. He has the home run speed that we’ve all seen. … And he’s only going to get better with every carry he gets, as he’s shown.”

One underrated part of Murray’s game is his pass-blocking, and that’s why he won’t lose too much time to two 5-foot-8 rookies.

“He doesn’t miss protections,” Carr said. “He sticks his face in there and keeps me clean. That’s the most important job a running back has. You’ve got to protect the quarterback.”

Some might say the most important job is ripping off big gainers and scoring touchdowns. And that’s why Murray spent his offseason back home in upstate New York, running with weights while trainers threw big exercise balls at him.

“It’s all about getting to the second level, making defenders miss and having a lot more explosive runs,” Murray said. “That’s what people were excited about in that Kansas City game (in 2014), that 90-yarder.

“They want to see those kinds of runs, and I do, too.”

Murray also continues to work at staying low when he runs.

“You just have keep pounding it in his head, and keep working at it in practice,” Raiders running backs coach Bernie Parmalee said. “Sometimes he doesn’t realize he’s high. And we remind him, so he doesn’t take that unnecessary punishment. ‘Stay behind those pads.’

“Defensive players don’t want to see 6-3, 227 pounds coming that low at them.”

Sometimes, the target is just too big.

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