Health was the issue for Diaz last year, but he is ready to leave the list of various injuries behind him. He began playing catch on Monday, the start of his throwing program, and he caught Angel Sanchez's bullpen session Tuesday.
"I'm going to be good. Right now, I'm 100 percent," said Diaz, the Pirates' No. 9 prospect according to MLBPipeline.com. "I'm good. We have to go step by step."
After making his Major League debut in 2015, Diaz played one game for the Pirates last year and only 25 for Triple-A Indianapolis, where he hit .266 with a .587 OPS. It all began in Spring Training, when Diaz's right elbow began to bother him. The nagging pain kept him off the field and led to surgery in May. He made it back to Indianapolis, but not until late July.
After the end of the Triple-A season, Diaz wasn't called up to join the Pirates. Instead, he was shut down and sent back under the knife, undergoing surgery to address an infection in his left leg. Diaz returned to the field for winter ball in his native Venezuela, but he was again sidelined in December, this time by an oblique injury.
Diaz said he felt a "little cramp" after one swing, and an MRI revealed a "little" injury. Still, it was enough for him to step away and begin resting for Spring Training. He said he has not yet resumed hitting, but he has been taking part in the Pirates' voluntary workouts this week.
Diaz's injury-plagued season was even more frustrating given the Pirates' occasionally desperate need for catching. The 26-year-old was Pittsburgh's clear-cut third catcher entering last year, and he appeared to be ready for the Majors if a need arose.
Sure enough, it did. Several times. But Diaz's own injury issues kept him from filling the void behind the plate.
Francisco Cervelli was limited to 95 games behind the plate, and Chris Stewart caught in only 31 games. The Pirates had to turn to journeymen catchers Eric Fryer and Erik Kratz along with Jacob Stallings, who began 2016 on the Triple-A depth chart as Diaz's backup.
With Cervelli and Stewart returning this season, Diaz is set to start for Indianapolis. If another opportunity presents itself in 2017, Diaz hopes to be ready. Call it a New Year's resolution.
"In my position, you can be frustrated. But it's baseball," Diaz said. "You have to know and separate everything. I was in the position that I was hurt. At that time, Cervelli's hurt, Stewart's hurt -- nothing I can do, because I was hurt.
"You have to have a strong mind, know what you want to do. That's it. Know where you want to be and don't lose it in your mind."