PHOENIX -- For the past few weeks, Kevin Towers has made the rounds of his club's Minor League teams.

Triple-A Reno, Double-A Mobile and both Class A Visalia and South Bend have received visits from the D-backs' GM, as well as other members of the baseball operations staff, in anticipation of the upcoming July 31 non-waiver Trade Deadline.

"At the Trade Deadline, if we're active, we're going to be asked about a lot of these guys. So I figured it was in my best interest to lay my eyes on everybody," Towers said.

The D-backs are likely to be asked about their Minor League prospects, because as a team in the thick of the National League West, they will be looking to add an established player. And at this point, their most pressing need, in Towers' mind, is in the bullpen.

The club has had to ride setup man David Hernandez -- who is in his first full season as a reliever -- hard, and it would like to add another veteran setup man. One thing it will not do, though, is part with some of the organization's top talent at this point.

"I would say we're less likely a seller now, and more likely a buyer," Towers said. "So you do your due diligence -- identifying what you think your major needs are going forward and identifying guys with clubs that may end up being sellers, and making sure you're getting multiple looks at those guys. If a club starts moving toward talking trade, you don't want to be scrambling to send guys out there; you want to make sure you've already had fresh looks at guys."

Towers' special assistants Bob Gebhard, Mike Fetters, Jerry Krause and Bill Bryk were among those dispatched to take a look a closer look at the Minor Leaguers.

Relief help will likely come in the form of a trade -- the D-backs have recently tried some internal options in Yhency Brazoban and Alberto Castillo. But additions for the offense or the starting rotation is more likely to be internal.

Two names to keep an eye on when it comes to starters are Reno lefty Wade Miley, who was recently promoted from Mobile, and Mobile lefty Patrick Corbin, who was acquired by the D-backs from the Angels in the Dan Haren deal last year.

On the hitting side of things, Reno outfielder Collin Cowgill and Mobile first baseman Paul Goldschmidt could be turned to for help.

"Starting pitching, I'm still keeping my eyes on guys like Corbin and Miley," Towers said. "Miley, we talked about him in camp and [he] has thrown very well of late. Corbin has thrown very good, also. I'm also keeping an eye on Cowgill and Goldschmidt, too. Some of our moves at the Deadline could be elevating people from our own system that are prospects to help us out at the time. Could be some internal promotions, or it could be trades."

The D-backs' ownership has told Towers that he will have some financial flexibility if he wants to add some payroll at the Deadline.

"We're going to look to improve the team, and if that means adding to our payroll, we're willing to do that," D-backs team president and CEO Derrick Hall said. "We've told K.T. and the baseball staff that we're supportive of them. We certainly like the position we're in right now, so any area that we can improve upon and have that possibility, we're going to tell them to aggressively seek it."

That's music to Towers' ears, but it also carries with it a responsibility that he takes very seriously.

"I want to make sure that if we take that step, it's the right person," Towers said. "I don't believe in making moves just to make moves, I want it to make a difference. So I'm going to make sure we're prepared, and have thought it out and decided what our real needs are. I don't think we're in a position where we're going to do a lot of different things. But if we decide to address the 'pen, we need to address the 'pen in the right way with the right individuals."