Scott Diamond was the only Minnesota Twins starter who pitched well enough last season to retain his spot in the rotation for this year.The left-hander's 2012 breakthrough featured a 12-9 record for a 96-loss team and a 3.54 ERA in 27 starts. Acquired before the 2011 season in the Rule 5 major league draft, Diamond struggled his first year with the Twins organization until finding his groove last spring.His next challenge will be to get healthy in time for the regular season.Diamond had surgery in December to remove a bone spur and chips from his pitching elbow. The 26-year-old said Wednesday on the first day of pitchers and catchers workouts that he hopes to be ready for opening day and that he is on a program to regain the strength in his throwing arm."We're pretty strict about our throwing program," Diamond said. "Right now, I'm throwing at about 120 feet, so we're moving along. At this point, it's tough to say. A big determining factor will be how everything feels when I get back on the mound. At this point, everything feels really solid. At this point, we're trying not to rush it because the whole season is more important than the first couple of weeks."Diamond, 26, went from not making the Twins out of spring training in 2012 to becoming the team's most consistent starting pitcher and the only holdover from last season's staff as 2013 begins. A year ago, he struck out 90 in 173 innings."Fantastic," Twins manager Ron Gardenhire said. "He was our best pitcher, no doubt. He has come a long ways. He has developed, and he's still developing. But he knows what he's doing out there on the field, and it shows."Diamond developed a blister late in the 2011 camp, and the Twins already had their rotation set with Carl Pavano, Scott Baker, Nick Blackburn, Francisco Liriano and Brian Duensing."I just remember all the guys had their bags in front of their lockers," Diamond said. "There were like 27 guys. Everybody else was packing, getting ready to leave that day. I'm sitting here in my chair, wondering if I would have to go back to Orlando with the Braves or head to Triple-A. I ended up getting pulled into the office at around 11 in the morning. They told me they were able to make a trade."Diamond had little success in the big leagues in 2011. He had a 1-5 record with a 5.08 ERA in seven starts with 17 walks but 19 strikeouts in 39 innings.Talks with Pavano and pitching coach Rick Anderson helped better prepare him for 2012, Diamond said."Definitely something clicked," Diamond said. "I think when I got to camp in 2012, I got to talk to a lot of the pitchers about how to be successful and how to be more durable at the big-league level. When I had my spring in 2011, my numbers weren't great, but I kept throwing deeper into games. I wanted to build off that."Mike Pelfrey, Kevin Correia, Richard Harden, all newcomers to the Twins, are expected to fill out the rotation, with a number of candidates competing for the fifth spot."He's got good stuff," Gardenhire said. "We liked him from the get-go. It's all about developing pitches, and he's done that."Because of his own lack of experience with the Twins, Diamond said he was not yet comfortable being declared the "staff ace.""I'd love to work myself into that role," Diamond said. "But with all of the guys we have, it's going to be a fresh start for everybody."Notes: Gardenhire said with catcher Joe Mauer in the World Baseball Classic for Team USA, he would be in good hands with Joe Torre managing. Gardenhire anticipated Mauer catching five to six innings per game before moving to the designated hitter slot. ... George Toma, who has presided over every Super Bowl as head groundskeeper, is missing the start of spring training for the Minnesota Twins for the first time since taking a part-time job with the team in 2002. Toma, 86, discovered a blood clot in his leg at the Super Bowl in New Orleans. Toma is recovering at home in suburban Kansas City.