"You go from doing something that you've done every single day for pretty much your entire life, and you have an injury like this and you can't do anything that relates to it even closely for four months, and it's just kind of crazy," Hudson said. "When your team is out there fighting hard and trying to get on a winning streak and you're sitting at home or in the dugout just watching and can't do anything to help, it takes a mental toll on you."
Hudson began rehabbing toward the end of the regular season and began throwing a tennis ball the first week of November.
"I was obviously wondering, 'Is it ready to go?'" Hudson said of his thoughts prior to throwing for the first time. "The first one was kind of hesitant and then it's like, 'I know how to do this.' It's like getting up and riding a bike again.
"We started slow, we started throwing a tennis ball for the first week just to get that motion back, and that was actually more difficult than throwing a baseball because it was so light. I had no idea where that tennis ball was going. The next week we were just tossing a baseball back and forth -- I don't think it was even 30 feet. And then we just progressed it from there like 15 or 20 feet every week."
In December, Hudson was playing catch from just over 100 feet.
Initially, his workouts took place near his home in Gilbert, Ariz., with D-backs head athletic trainer Ken Crenshaw. Hudson was given a few weeks off to head back to his native Virginia for the holidays, and when he returned, he and Crenshaw began working at the team's Salt River Fields Spring Training facility.
Hudson was expected to be a key part of the D-backs' rotation last year after going 16-12 with a 3.49 ERA in 33 starts in 2011. However, shoulder problems and then the elbow injury limited him to just nine starts.
The D-backs' starting rotation figures to be Ian Kennedy, Trevor Cahill, Brandon McCarthy and Wade Miley, with the fifth starter likely coming down to rookies Tyler Skaggs and Patrick Corbin.
So far there have been no setbacks in Hudson's rehab, and he is hopeful that he can return to the Arizona rotation in July.
"Obviously, you don't want to rush it because it's such a major injury, but I would say around the All-Star break either right before or right after would be pretty realistic," Hudson said. "That would put me right at 12 months, which is pretty close to average for people to recover from Tommy John. If it's a couple weeks before, it could happen that way, or if it's a couple weeks after, it could happen that way, but I would say the All-Star break is pretty realistic."