Sinker Has Frank Duncan On Rise

PHOENIX—Righthander Frank Duncan has always thrown a two-seam fastball. He just never envisioned it as his primary pitch.

But since shifting to a sinker-heavy starter midway through 2015, Duncan has seen his stock rise as a prospect, to the point that he caught the attention of the Diamondbacks, who acquired him in February when they sent second baseman Phil Gosselin to the Pirates.

Duncan said it was his high Class A Bradenton pitching coach Scott Elarton who suggested he start using his two-seamer more often, seeing it as a weapon that could put him over the top.

“It was one of those things where I would try to do a whole lot of things OK instead of just one thing really well,” said Duncan, 25. “When I narrowed that focus and started doing the little things really well, that’s when it got better for me.”

The results are hard to overlook. In 138.2 innings at Double-A Altoona and Triple-A Indianapolis in 2016, Duncan recorded a 2.34 ERA and allowed just four homers. He ranked among the International League leaders in groundball rate.

Duncan, who also throws a slider and changeup, says he’s continuing to refine his sinker, which he says generally sits in the 88-90 mph range.

“Last year was the first year I was actually committed to it full-on from the beginning of spring training until the end,” said Duncan, a 13th-round pick in 2014 out of Kansas. “It led to a lot of success for me. This will be my second year with (this approach). I feel like if I can get better at throwing to spots rather than just letting the (two-seam) action work, it’s just going to continue to get better.”

The D-backs believe Duncan could help sooner than later.

“We think he protects us both as a starter and possibly as a reliever,” general manager Mike Hazen said. “I think there could be some untapped potential for him (in the bullpen) at the major league level as he breaks in. ”

SNAKE BITES

• Outfielder Socrates Brito, who had surgery in November to remove a fractured right hamate, was fully healthy for the start of spring training, Hazen said.

• Japanese lefthander Yuhei Nakaushiro was in big league camp vying for a bullpen job after posting solid numbers at four levels last season.

— Nick Piecoro covers the Diamondbacks for AZCentralSports.com