OXNARD, Calif. – The most-discussed position battle of training camp hasn't even happened yet, but it begins on Saturday.

Ronald Leary hit the Cowboys' practice fields for the first time on Thursday, participating in the morning walkthrough and the individual portions of practice. Leary began training camp on the Physically Unable to Perform List last week when he tweaked his hamstring in a conditioning test, but he was added to the active roster Thursday morning.

"You never want to get hurt and stand on the sideline watching your brothers out there play, but it feels good to be back," he said.

The purpose of Leary's individual work was to determine if he was ready to go in a full-fledged practice. There wasn't much doubt about the verdict, as he said he felt 100 percent in testing the hamstring.

"I'm going – I'm good," he said. "Today was just to see how it was, being able to push up against somebody, and there were no problems, so I'm full-go."

With Leary returning to the practice field, the oft-mentioned left guard battle can begin in earnest. Veteran Mackenzy Bernadeau has manned the left guard spot for the duration of training camp after rotating with Leary during the spring.

Leary and Bernadeau both started last season, but with first-round pick Zack Martin expected to start on the right side, there's only room for one on the first-team line.

"When I wasn't in, me and Mack were still talking about stuff. We all know in the NFL it's a competition all the time, so we take nothing personal, we're just going to try to get better," Leary said. "At the end of the day, they're going to decide who the best man is and that's who's going to play."

Quick Hits:

• Leary might be back to work, but the Cowboys lost three more players to injury during Thursday's practice. Most notably was Dwayne Harris, who twisted his ankle during a particularly heated one-on-one rep against Terrance Mitchell. The rookie cornerback brought Harris to the ground on the play, which drew sharp criticism from coaches and players. Harris worked on the ankle with trainers before leaving the field.

• Defensive lineman Ben Bass tweaked his hamstring during defensive line drills around the same time as Harris. Minutes later, Darrion Weems hurt his shoulder and was escorted from the field after he was injured going against Tyron Smith in an all-offensive line drill.

• Cornerback Sterling Moore didn't practice at all after participating in walkthrough. Moore was sidelined by a groin injury.

• As the Cowboys split off into position groups, Garrett's focus was on the 1-on-1 red zone battles between the receivers and defensive backs. The receivers jumped out to an early 4-2 lead until an Orlando Scandrick interception. "Four to four now," Garrett said. "You get two for an interception." Scott Linehan took exception to the rule. "Do we get two for a touchdown?" Linehan said with a smile. The receivers, particularly Dez Bryant, won a lot during that drill, but it resulted in the injury to Harris.

• The 2014 Blue/White Scrimmage will be held on Sunday, August 3 at 2:30 PT. Fans can tune into KTXA 21 where Bill Jones and Babe Laufenberg will have the call. Brad Sham and Bryan Broaddus will offer play-by-by and color analysis on 105.3 The Fan and on the web at www.dallascowboys.com. [embedded_ad]

Notable Standouts:

• Terrance Mitchell –The young cornerback continues to show up in practice, for good and bad reasons. There's no denying Mitchell's tenacity, as he jumped the line to get as much work as possible in one-on-one drills against wide receivers. Mitchell held his own against everyone – he was the only defensive back to hold Dez Bryant without a catch in one-on-one drills. Unfortunately, his aggressiveness gets him in trouble. Aside from hurting Harris, Mitchell drew criticism for knocking Lance Dunbar to the ground in special teams drills.

• Davon Coleman –Coleman continued to turn heads with his pass rushing ability – in both individual drills and team work. Defenders aren't allowed to hit quarterbacks in practice, but Coleman would have had quite the sack if they were. In team drills, he blew past Mackenzy Bernadeau and was right in Tony Romo's face within seconds.

• Dashaun Phillips –Another unsung defensive back had a strong showing. He squared off several times against Terrance Williams and Boyd and didn't lose grain.

* *

Play of the Day:
Chris Boyd continued his trend of making standouts catches during practice, as he caught a low pass in the crook of his arm in the back corner of the end zone for a one-handed touchdown. His momentum carried him well out of bounds, where he knocked over a photographer.

Injury Report: Left Practice:WR Dwayne Harris (ankle)
OT Darrion Weems (shoulder)* DL Ben Bass (hamstring) *

Returned to Practice:OG Ronald Leary (hamstring)* *

*Missed Practice: *CB Sterling Moore

OG Brian Clarke

CB Morris Claiborne (knee) 

DE DeMarcus Lawrence (ankle)
DE Anthony Spencer (knee) 
DT Amobi Okoye (illness)
CB Brandon Carr (personal matter)
DE Ben Gardner (shoulder)
DT Terrell McClain (ankle)
LB Will Smith (groin)
* *

Upcoming Schedule:

Friday, August 1

No Availability                    Player's Day Off

Saturday, August 2

10:30 a.m. (PT)                    Walk-Thru

12:00 p.m. (PT)                    Coach Garrett Press Conference

3:45 p.m. (PT)                       Practice

Sunday, August 3

2:30 p.m. (PT)                       Blue/White Scrimmage

TBD                                         Coach Garrett's press conference will be held approximately 30 minutes following the conclusion of the Blue/White Scrimmage