ARLINGTON -- The Cowboys started two rookie offensive linemen in the preseason opener Thursday night and coach Jason Garrett, while noting he needed to see some tape of the two, said the big stage didn't scare them.

First-round draft pick Tyron Smith started for the Cowboys, and coach Jason Garrett said he was pleased that Smith and fellow rookie David Arkin played "with a little confidence." Matthew Emmons/US Presswire

First-round pick Tyron Smith started at right tackle and fourth-round pick David Arkin started at left guard Thursday night against the Denver Broncos.

It appeared Smith had just one noticeable mistake. He missed a blitz pickup that led to a Stephen McGee sack in the second quarter. Arkin was pushed back a few times, but it seemed he played OK.

A full evaulation of how the rookies played will come Friday morning when the coaches watch video of the performance.

"One of the things that we were pleased with is they didn't seem like [the game] was too big for them when they were on the sidelines," Garrett said. "They seemed to play with a little confidence. I'm sure they had some butterflies. It was a new and different experience for them than what they're used to, but you like to see them just go out there and play like it's regular football like they've been playing their whole life. From the naked eye, looking in their eyes, it seemed like they seemed OK with it."

After the first-team offense left the field after one series, Arkin and Smith stayed on the field and were joined by Pepa Letuli at right guard and Jermey Parnell at left tackle. Phil Costa remained at center.

At the start of the second half, the Cowboys offensive line consisted of Parnell, Kevin Kowalski at guard, Bill Nagy at center, Letuli, and Sam Young at left tackle.