"It's been a lot of work," he said. "The moment I got cleared in September, I started swinging immediately. It's been a good five or six months of hard work. It's good I was a two-way guy in college so I was always swinging. ... It's something I always wanted to do since I loved it so much, and I was pretty good at it, and based on the circumstances because the arm has been through a lot, it's nice to have something to fall back on and to keep playing this game as long as you can."
Armstrong, whose father played seven years in the Majors with the Reds, Marlins and Rangers, never pitched in a game after being drafted by the Astros. A pre-Draft MRI showed a damaged ulnar collateral ligament, and when he couldn't rehab it naturally, he underwent Tommy John surgery.
"We found out it was 80-percent torn and that's what I was pitching through in college," he said. "I went through the surgery, rehabbed it and worked my tail off, and it was feeling really, really good. I started throwing and my shoulder was bothering me."
Believing he had biceps tendinitis, Armstrong backed off throwing for a few months, but the pain was excruciating. An MRI late in 2012 didn't show much, but a trip to noted orthopedic surgeon Dr. James Andrews diagnosed a complete labrum tear six months later. Another surgery followed, and Armstrong's pitching days were done.
"It was unfortunate I wasted that much time, so here I am now trying to give it another shot," he said.
Armstrong, 24, still has a long road ahead of him to try to prove himself as a first baseman, and the early returns in batting practice have been good.
"It's like riding a bike, a really tough bike," he said. "The first couple of times, it was really difficult. Seeing 92 [mph] was like seeing 98. Once I started seeing a lot of pitches, I came here two weeks early and started seeing live pitching and did really well. The power is really there. I'm hitting the ball a long way. Now we have to get consistent with my swing and hit the breaking pitch."