"The Arizona Diamondbacks, losers of three straight, swapped relievers with their Class AAA affiliate on Tuesday: right-hander Yhency Brazoban and left-hander Alberto Castillo are in; righties Esmerling Vasquez and Bryan Shaw are out.

And if those fixes don't work, more expensive bullpen reinforcements could arrive soon.

Diamondbacks president/CEO Derrick Hall told FOXSports.com on Tuesday that first-year general manager Kevin Towers will have the ability to add payroll leading up to the July 31 non-waiver trade deadline.

"We've got the flexibility," Hall said in a Tuesday telephone interview. "Our ownership group is willing to invest in this team. We've told KT, 'If we're in it, we'll do whatever it takes to support you.'"

Arizona opened the season with a payroll of $53.6 million, sixth-smallest in the majors, according to the USA Today salary database. And now the Diamondbacks have become one of the surprise teams in baseball; they entered play Tuesday night only 2 1/2 games back of San Francisco in the National League West."