Diamond sustained a bone chip in his throwing elbow while jumping rope, and ended up needing surgery in December that could delay his projected Opening Day start.
"It was kind of a freak mishap, really," Diamond said. "I was in the middle of a workout, I was actually jump-roping, skipping, and right as I was finishing up that rep, I felt a crack in my elbow. That was when I felt something. I tried to bench and it didn't feel right, so we shut it down."
Diamond has been rehabbing his elbow since undergoing the operation, and only recently began throwing off a mound again. He threw 20 pitches at about 55 feet on Tuesday before throwing 25 pitches at about 60 feet on Wednesday.
He's tentatively scheduled to throw a full bullpen session on Friday before facing live hitters next week. And if all continues to go well, he could be pitching in Grapefruit League games by the second week of March.
So while he's not ready to make any predictions about being ready for the season just yet, he's happy with his progress.
"The ball is coming out good but it's just about finding the mechanics and that release point," Diamond said. "Everything is lining up, which is positive. I'm just trying to get out the kinks, but structurally it feels awesome. I'm not having any discomfort or tightness the next day. So basically, the recovery is going really well."
The hardest part for Diamond is trying not to rush back to action, as he knows, if healthy, he'd be the club's top candidate to start on Opening Day against the Tigers on April 1 at Target Field.
If Diamond isn't ready to go, the Twins could opt to start new addition Vance Worley or veteran Kevin Correia.
"I think I still have my sights set on April 1, but it's tough to continue to focus on that," Diamond said. "Actually, it's probably tough not to focus on it when everything feels so good right now. But we're just still trying to take it nice and easy, focus on hitting those big steps, getting full distance off the mound, facing hitters and then getting into a game. I've got a couple of steps to make before that really happens."
Twins coaches, including pitching coach Rick Anderson, are making sure Diamond sticks with the throwing program, as the last thing they want is for him to experience a setback in the spring. The Twins also only need four starters to open the season, with an off-day on April 2 after their home opener.
"We're not going to get too far ahead with him," Anderson said. "We'll just play it as it progresses. I know he wants to be [ready for Opening Day], but we'll see as we go."
Diamond, though, certainly made a strong case to be the club's top-of-the-rotation starter this season after leading the staff in wins (12), ERA (3.54) and starts (27) last season.
He was a pleasant surprise, considering he was sent to Minor League camp in the first round of cuts during Spring Training and had posted a 5.08 ERA in seven starts with the Twins in 2011 after being acquired in the Rule 5 Draft from the Braves.
"He's come a long ways," manager Ron Gardenhire said. "He really handled himself very well. He was a student of the game. Really studied it. Paid attention. He had a plan each game. He knew what he was going to do. He executed very well. He was, I'm not saying a total surprise, but he stepped up and came a long way in a short time for us last year. He really was a bright spot for our baseball team last year."
So for now, Diamond is just trying to take it one step at a time as he tries to prepare for his sophomore campaign with the Twins.
"That's the big thing right now," he said. "We still have eight days in February and then an entire month. So I have to be really positive. I think the coaching staff has to be pretty positive with where we are right now."