CHICAGO -- Zack Burdi departed Glendale, Ariz., for Louisville, Ky., with a positive mindset in his ongoing recovery from Tommy John surgery, despite being shut down in the Arizona Fall League due to arm fatigue.
"What I've expressed, and what the Sox have expressed back to me, is that this was a long process -- 15 months -- and my arm was getting tired. It was time to just relax," Burdi told MLB.com by phone from Phoenix on Friday afternoon. "We worked 15 months and there's got to be a little down time during the offseason in order for it to work and in order for it to bounce back.
"Take these next six weeks and allow that to happen, and really focus on nutrition and physical therapy and offseason training that I really haven't been able to do the last year. It's going to be a good six weeks to mold myself back into what I believe gives me the best shot at what I'm trying to reach and get into a throwing program and getting ready for spring."
Burdi, the No. 17 White Sox prospect per MLB Pipeline, had his surgery on July 27, 2017. The 23-year-old right-hander was back in action on Aug. 4 of this past season pitching for the organization's Arizona Rookie League team and allowed two runs over 6 1/3 innings in seven games with seven strikeouts and four walks.
His last AFL outing for Glendale came on Oct. 23, leaving Burdi with no earned runs given up over five appearances which totaled 4 2/3 innings. Burdi has seen pain-free progress in every one of those 12 outings since early August, pointing to the renewal of his slider, the changeup emerging as his best pitch and the consistency of his fastball as things instilling more confidence.

"It kind of showed me I'm on the right track," Burdi said. "Everything is good, trusting the process. ... I was really excited with the Fall League and my five outings.
"I faced a lot of guys that were big name dudes in their respective organizations and had really competitive at-bats. There's a lot of positives to take away. At the end of the day, the whole point was to end the recovery healthy, and we did that. It was time to shut it down after a long 15 months of rehab and throwing. Definitely happy that I'm healthy going into the offseason."
As for fastball velocity, with Burdi being previously known to hit 100 mph, he's not worried about readings at this point. Burdi quipped a "good group of guys" on Twitter "tend to Tweet at me upset about where my velocity is at."
"They have given a good reading on me," Burdi said. "I hit a (95) and showed some (96) and (97), which apparently doesn't sit well with some people, but it's Tommy John. It's something you have to work for. It's a tough recovery.
"My freshman year of college I was 89-to-91 and worked my tail off to get to where I was at the end of my junior year. I wasn't blessed with a great arm. It's something I had to work for, for a good amount of time. I'm aware I have to go back to that process and put myself through that, day in and day out workouts and preparation, in order to get back to that point.
"I'm ready to do that. I haven't really been too focused on it and not too concerned where my velocity is at. I'm more concerned about being able to throw strikes and compete in at-bats. I was able to do that with what I had in me. That's great. That's a positive, and it's something that I should hang my hat on."