The 23-year-old Blue Jays right-hander tore his left anterior cruciate ligament fielding bunts during a pitchers' drill Tuesday.
Stroman, wearing a We The North baseball cap when he met with reporters Wednesday, said initially it was hard to keep his emotions in check.
"It's tough. It's more of the fact that I just feel like I let my team down," he said outside the Jays spring clubhouse. "I've worked harder than I ever had this off-season. And to not be able to go out there and compete every day with the brothers that I have kind of developed a relationship with and a camaraderie, it sucks. It's so unfortunate.
"That's the hardest part, not to be around some of my best friends in the game, to be way from them."
On Wednesday, Stroman was positive about his pitching future. He said he had been buoyed by calls to his family and support from all over the league.
Stroman says he will dive into his rehab with a smile on his face and get it done.
"Honestly I feel like a lot of people are more worried than I am," he said. "I know I'm going to be fine. I know I'm going to come back probably stronger from this. I know that once 2016 comes, I'll be ready to rock and I'll have my goals set even higher than I did this year. ... We'll get past it, we'll move forward and we'll be good."
It was the second significant training camp injury for the Jays. Canadian outfielder Michael Saunders tore the meniscus in his knee in a freak accident when he stepped into a sprinkler head indentation while shagging fly balls.
The prognosis was better than expected for Saunders after having 60 per cent of his meniscus removed. He could be ready for Opening Day.
Stroman said his injury happened on a play "as routine as it comes."
"I was going after a ball and just planted and it just popped. It was just one of those things. I've heard of people tearing their ACLs just walking. Like it's just a freak accident. No one's to blame. It's not the field, it's not anything, it wasn't (third baseman Josh) Donaldson. Obviously he reached out to me because he felt bad but I told him 'Listen, this isn't your fault. It's just something that happened.'"
Donaldson called Stroman off the ball on the play where the injury happened.
Stroman's injury leaves another hole in Toronto's starting rotation. Aaron Sanchez, Daniel Norris and Marco Estrada are expected to compete for two spots in the rotation alongside R.A. Dickey, Mark Buehrle and Drew Hutchison.