COLLEGE PARK — One-on-one pass-rushing drills are among the ultimate tests for an offensive lineman.

They are on an island, have no help, and any error or misstep could lead to a sack and embarrassment.

But Maryland freshman right tackle Derwin Gray excelled during that drill Tuesday and continues to impress teammates through the early part of preseason practice.

Gray’s final three turns during the drill came against two of the Terps’ top pass rushers. He stopped defensive end Quinton Jefferson twice and forced a wide rush from outside linebacker Yannik Cudjoe-Virgil on the other turn.

Offensive line coach Greg Studrawa was standing behind the action. After each of the three matchups, he yelled enthusiastically, “Yeah, Derwin.”

“He’s working hard,” senior center Sal Conaboy said of Gray. “Like any freshman the second day of camp, it’s tough. [He’s] got to get in his playbook like anyone else, but he looks good.”

It helps that Gray is not a typical freshman.

Gray originally signed with Maryland out of Friendship Collegiate Academy last year, then he spent last season at prep school.

Gray was unable to participate in spring practice with the Terps after undergoing shoulder surgery, but he was able to sit in on all of Maryland’s offensive line meetings and took part in all of the Terps’ summer workouts.

“Technically he’s kind of like a sophomore,” Cudjoe-Virgil said. “He’s not one of those guys that’s coming straight out of high school fresh. He’s got some coaching on the college level to his game, so he’s definitely [come] out here and shown he can play.”

Gray is also more advanced physically than many freshmen. He is listed at 6-foot-5, 300 pounds.

While Gray squatted during one workout session, quarterback C.J. Brown said one of Maryland’s strength coaches came up to him and said, “You’re lucky to have that guy in front of you.”

Gray entered preseason practice listed as the backup to Ryan Doyle at right tackle, but he could push for the starting job if he continues to look as good as he did Tuesday.

“It’s too early to even talk about those guys,” coach Randy Edsall said of Gray and fellow freshman lineman Damian Prince. “With offensive lineman, you’re never going to see anything in terms of what you want to see out of them until you put the pads on. They’re both great kids. Love them to death. They have ability. How quickly or how hard they want to work [and] how much time they want to study the playbook will determine how fast their development will go, and how coachable they’re going to be will determine where they are.

“We’ll really reserve judgment until we get a little further down the in preseason when we can make a fair evaluation.”

Open competition?

Edsall was openly critical of punter Nate Renfro near the end of spring practice, and Renfro could be pushed for the Terps’ punting job by preferred walk-on Lee Shrader.

Renfro has been Maryland’s punter since his redshirt freshman season in 2012, but he averaged just 39.7 yards per punt in 2012 and 40.8 yards per punt last season. He also struggled during the spring, enough that Edsall said, “I don’t think Nate’s had a good spring.”

Preseason camp is only two days in, but Edsall said before practice Tuesday that Renfro was inconsistent during the first day.

It is too early for Edsall to have a great feel for Shrader, but he did say the freshman from Newport News, Va., has a strong leg.

“We’ll see if he can be consistent day in and day out and consistent with the drop,” Edsall said of Shrader. “That’s something we’ll have to continue to work on and continue to evaluate. And as we get into more practices, we’ll see how that all kind of shakes itself out.”

OTHER NOTES: Prince was bulled over by outside linebacker Yannick Ngakoue during one-on-one pass rushing drills, but he bounced back and kept the next player he was matched up with from getting a sack. Prince also prevented a defender from getting a sack during an earlier turn. … Edsall was complimentary of sophomore running back Wes Brown. Brown was suspended last season and put on 10-15 pounds of bad weight while he was away, but Edsall said, “He knew he needed to be in the best shape he could be coming in here, and he got himself to that point.” … Left guard Evan Mulrooney missed practice Tuesday because of an illness.