SURPRISE, Ariz. -- These days, Royals prospect Kyle Zimmer is keeping expectations low.
Zimmer, the Royals' No. 9 prospect according to MLBPipeline.com, arrived to Spring Training in 2016 with great optimism. His fastball was hitting 96 mph early in camp.
And then Zimmer suddenly hit a wall. His velocity began fading to the upper 80s. Sharp pain in his shoulder area became a constant.
Eventually, Zimmer was shut down. In fact, he pitched in just three Minor League games last season before some exploratory surgery revealed he could benefit from thoracic outlet syndrome surgery, which he then had in early August.
Now, Zimmer, 25, has rehabbed and feels as strong and as pain-free as he can remember.
Zimmer threw his second bullpen session of camp Tuesday, and reported no pain on Wednesday -- just the normal soreness associated with throwing batting practice.
"It feels good," Zimmer said. "A little sore and a little stiffness, but not a lot.
"It's just normal soreness. Nothing like the sharp debilitating pain from last year."
After years of injury issues, Zimmer, the Royals' first-round Draft pick in 2012 (fifth overall), is hoping health concerns are a thing of the past.
In past years, Zimmer has had his elbow cleaned, had tissue in his rotator cuff repaired, and underwent surgery to his latissimus dorsi muscle.
This may be the year Zimmer can reach all of his potential. He is a right-hander who the Royals routinely used to describe as having the best stuff in the system.
"He's looking good this spring," manager Ned Yost said. "He's throwing nice and easy."
Zimmer is simply happy there is no more pain.
"At this point last year, I was starting to struggle, starting to taper off," Zimmer said. "I'm feeling much better now."
While Zimmer has said there are no limitations for him this Spring Training, he doesn't want to get too carried away early.
"Coming off the surgery I was told there'd be ups and downs," Zimmer said. "But it's important to keep the highs and lows a little more consistent. You just want to keep your body in the best shape and go after it."
On Sunday, Zimmer will make his first Cactus League start.
"I just like getting back into the swing of things," he said. "I'm excited to get to the start of games and transfer it all over to the start of games."
Jeffrey Flanagan has covered the Royals since 1991, and for MLB.com since 2015. Follow him on Twitter @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.