Romo missed the final game of the 2013 season to undergo back surgery and is on target in his rehab program.
In the first phase of the offseason workouts, players can lift weights, run sprints and conduct football activities without the supervision of coaches and scouts.
This is the first of several offseason workouts the Cowboys will conduct. After the May 8-10 NFL draft, the Cowboys will host a rookie minicamp the following weekend.
Starting on May 28, the Cowboys will have organized team activities until June 12.
The offseason program ends with the mandatory veteran minicamp June 17-19.
Romo's availability is expected in most, if not all, of those activities. League sources told ESPN NFL Insider Ed Werder that Romo continues to follow the rehab protocol, which also includes light jogging and working out in the team's weight room using cardio equipment.
Last summer, Romo missed several days of the offseason program as he recovered from surgery to remove a cyst from his back.
But last December, Romo underwent a discectomy to repair a herniated disk after injuring his back in a Week 16 game at Washington.
Team officials said Romo recovered well from the surgery.
"It's going good," Romo told ESPN in March after watching a Duke basketball game."We're getting close now to [returning]. Usually takes three months, it's just the normal kinda roundabout date that they give you, and we're right on schedule.
"Really ahead in a lot of ways. Just going to be ready to go here in about a month and rehab is going good, no setbacks of any kind. Mine [surgery] was just a normal small version of it, so I should be good to go here shortly."
Romo finished the 2013 season throwing for 3,828 yards with 31 touchdowns and 10 interceptions.