LHP Daniel Gibson
The D-backs selected Gibson in the seventh round of the 2013 First-Year Player Draft, and he had a combined 1.56 ERA in 53 relief appearances this year for Class A Visalia and Double-A Mobile.
Bell's take: "He's been an interesting left-hander out of the bullpen since we've had him. The most impressive thing is, he was able to do it consistently throughout the year in just every facet of what it means to be a professional. He took care of everything that he could control and his talent took over. He's not a gimmick pitcher. He's got arm strength and really good stuff."
RHP Yoan Lopez
Signed out of Cuba last offseason, 2015 was anything but smooth for Lopez, who compiled a 1-6 record with a 4.69 ERA in Mobile and missed time for what the team said were "personal reasons." He also had some blister issues as well as elbow discomfort that shut him down for a while.
Bell's take: "It was a learning year for him. I think that's the best way I can put it. I've seen him grow. He's been more comfortable around the staff and teammates. We built him up during the Instructional League and we want to get him as many innings as he can handle so that he's prepared for 145 or 150, or maybe more than that next year."
RHP Adam Miller
A 20th-round pick in 2013, Miller was 2-7 with a 2.88 ERA in 50 relief appearances for Mobile while touching 101 mph on the radar gun.
Bell's take: "Everyone always talks about how hard he throws, but it was probably the second month where he started pounding the strike zone, and it was impressive. I think for him it's just getting out there and doing it and doing it again and again and again to where he's consistent with his delivery, his arm slot and everything he's trying to do. I think he's got a chance to help us in the big leagues soon."
RHP Myles Smith
Acquired from the Red Sox last December for Zeke Spruill, Smith started the year in extended spring before pitching at four different levels, including one game at Triple-A Reno.
Bell's take: "It's a big jump for him, but his stuff is plenty good. When we got him, it was just right place/right time for us. I think he was a little bit of late bloomer. I also think [pitching coordinator] Dan Carlson did a good job with him and made him comfortable, and he just came a long way with his fastball command and his cutter/slider that he throws."