DUNEDIN, Fla. — Devon Travis will never forget the most difficult setback of his career. He's got the scar on his collarbone to constantly remind him.

Plagued by injuries over his first three major league seasons, Travis has been a full participant in this spring training for the first time in years.

And while his latest off-season consisted of yet another rehab process after having knee surgery in June, the Blue Jays second baseman said that was nothing compared to the shoulder injury he suffered back in 2015.

"Every injury you always wonder if you will be the same again," Travis said in Toronto's spring training clubhouse Thursday. "I guess I can speak on it going through so many injuries. ... but (with the shoulder) I had those doubts plus more because it had never been done before.

"It was a challenge, that was the toughest rehab I'd ever had."

Travis, who started hot out of the gates in April 2015, had his rookie season turned on its head the following month when he was hit in the collarbone by a line drive in Cleveland. The injury revealed that his shoulder blade had never properly fused, leaving fragile cartilage in charge of holding two pieces of bone together.

Travis learned the condition — known as os acromiale — is rare. Those who have it may go through life never even knowing.

Doctors weren't sure how to proceed with Travis' injury at first and some refused to operate. He needed two separate surgeries to correct the problem, including one in November 2015 that secured his bones together with screws, and sat out nearly all of spring training in 2016.

"Probably never would have been an issue if I never got hit," Travis said. "I've had it my whole life. It just happened to be the right ball at the right spot and it was hit damn hard and it got me."

His latest setback, a knee injury last June that required surgery to clean out cartilage in the joint, had him rehabbing all off-season but hasn't appeared to hamper him in camp this year.

Gibbons used Travis in back-to-back spring training games earlier this week, saying if he felt fine afterwards he'd know the injury would be behind him.

"That was the plan, I didn't think there would be any obstacle at all," Gibbons said. "It's something he can prove to himself."

Travis said the mental aspect of dealing with his latest injury took more of a toll on him this winter than the physical rehab.

He's had a strong support staff, led by new Blue Jays head athletic trainer Nikki Huffman, who helped keep him positive and focused on the bigger picture.

"Most things in life, when they happen over and over again, the more times they happen it becomes easier to deal with. But injuries it's like one of it's own," Travis said. "Every time something happens it gets harder mentally than anything. The rehab part you learn that it's a long process and you stay the course and you have to trust everyone you're working with and you have to trust the work you're putting in today is going to mean something in the future.

"But the mental part is the tough part, that's for sure."

Travis's goal for the upcoming season is simple, and expected.

"Stay healthy," he said sternly. "I just want to be there for my team when it counts. I understand that September is more important than April and I have to do whatever I can to get to that point.

"It's nice to be a normal guy (in camp), not a rehab guy. I just want to be there when it counts, that's it."