He recently landed a big power arm with the acquisition of veteran right-hander Heath Bell in a trade with the Miami Marlins, and Towers is monitoring some promising young bullpen arms developing in the team's Minor League system.
Three of them are pitching in the Arizona Fall League for the Salt River Rafters -- right-handers Eric Smith, Evan Marshall and Kevin Munson.
Smith -- like Munson -- is in his second tour of duty in the AFL, and he continues to make the transition from a starter to a reliever in the Minors.
After making 26 starts for two clubs in 2010 and 28 for Class A Advanced Visalia in '11, Smith had his first full year in the bullpen in '12 at Visalia (13 games) and Double-A Mobile (30 games), going 4-4 with a 4.11 ERA and two saves.
The 6-3, 220-pound Smith was 2-0 with a 5.12 ERA in 19 1/3 innings of AFL action in 2011, as Salt River won the championship. In his first five games in '12, he was 1-1 with a 2.57 ERA and a save in seven innings.
"Being out here this year has been better because I know more of what to expect, both from the hitters and with what I'm supposed to be doing," Smith said. "I feel a lot more comfortable.
"Last year, I didn't do as well as I would have liked. This year, I have bigger, higher goals. I'm working on the things I need to work on so I can put myself in a position to take that step [to the Major Leagues]."
When D-backs officials approached him with the idea of becoming a reliever after the 2011 regular season, Smith admitted he wasn't happy.
"I didn't think it was a good idea," Smith said.
"This year, I liked it. It is more suitable for me," Smith said. "I think I have reacted well, and I think they [the D-backs] are happy with the way I've accepted the role."
Smith said working out of the bullpen is akin to being an everyday player.
"When you're a starter, you might have a tendency to tune out some of the games you're not involved in," Smith said. "In the bullpen, you're constantly talking baseball, what to do in certain situations. You have to pay attention at all times."
Smith is drawing the attention of the D-backs as they monitor his progress. D-backs third-base coach Matt Williams is the manager of the Rafters.
"[Smith] is a guy who is capable of multiple innings," Williams said. "He has a power sinker with a good breaking ball to go with it."
Pitching can be as much of a concern mentally as it is physically, particularly if you are trying to become a reliever.
"It is no time to mess around," Smith said. "You have to go right at the hitters with your best stuff immediately."
Smith seems like a quieter, low-key individual much of the time, but he can change once he gets on the mound.
"I have that fire in me. The intensity is turned up," Smith said, "but at the same time, I've also learned to be more calm."
That didn't always happen when he was a starter.
"Sometimes, I let things get to me where they might spiral out of control. I wasn't able to take a step back and breathe," Smith said. "Now I am a lot better. I'm taking it one step at a time."
That's exactly what the D-backs want to hear.
Don Ketchum is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.