Tony Romo sees no reason to doubt owner Jerry Jones' projection that he will be the Dallas Cowboys' starting QB for four or five more years.

Romo, who turned 36 in April and is under contract through the 2019 season, is back on the field for organized team activities following surgery in March on his left collarbone. He was limited to four games last season after twice breaking that collarbone. He also had two back operations in 2013 but says he is confident in his durability.

"I'm not in my mid-20s anymore, but I do think based on what my situation has been like the last three or four years, I do think this [offseason] is drastically different," Romo told ESPN. "It takes me back five years ago when I was able to do things the way [I had]. I'm not there yet. I still got these months to just get after it, but it's exciting to actually be able to get after it a little bit. But if everything keeps going the way it's going, I think it's going to be exciting going into camp."

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Head coach Jason Garrett has been impressed thus far.

"He's healthier than he's been," Garrett told ESPN. "He's been able to go through more of the offseason program, lay the foundation for himself with [strength coach Mike Woicik] and his staff back there. I think his back feels better. I think he's come back from the surgery on his collarbone seemingly without any problems."

The Cowboys drafted Dak Prescott in the fourth round last month to perhaps serve as Romo's heir. However, the plan is for Romo to mentor Prescott for at least several seasons – perhaps as many as four or five seasons if Romo has his way.