CHICAGO -- The Chicago Cubs made the somewhat drastic move on Thursday of going with 13 pitchers on their roster and 12 position players one day after using three pitchers in a ninth-inning blown save against the Arizona Diamondbacks.

Blake Parker was sent down to Triple-A Iowa and outfielder Justin Ruggiano was placed on the disabled list allowing room for lefty Zac Rosscup and righty Neil Ramirez.

"Right now, at least for 15 days with Ruggiano down, and then we'll go from there," manager Rick Renteria said of using 13 pitchers. "We can use the pitching."

This comes on the heels of Cubs' starters going seven or more innings in the first three games of the series against Arizona but maybe Renteria was preparing for the next two days when Edwin Jackson (Thursday) and Carlos Villanueva (Friday) take the mound. Bullpens have been in use more often than not when they pitch.

But why did the Cubs choose to send down the righty Parker in favor of the lefty Rosscup? Maybe it has something to do with the lefties currently in the bullpen. James Russell and Wesley Wright have struggled, especially against left-handed hitting. Opposing lefty hitters are 5-for-10 against Wright this month and Russell has walked three and given up three hits, including a home run, in 11 at-bats against left-handed hitters.

"Rosscup has shown he's capable of relieving up here," Renteria said. "He did a nice job in New York."

Rosscup threw 1 2/3 innings of scoreless relief as the 26th man on the roster in a doubleheader against the New York Yankees but was sent right back to Triple-A. Wright and Russell could be showing signs of fatigue due to heavy workloads over the past two years. Both are at the top of the league in appearances over that time frame. Either way, the Cubs bullpen is a mess right now with no clear-cut closer and overuse or ineffectiveness is the common denominator.

"The reality is you win or lose ballgames in the seventh, eighth and ninth inning," Renteria said. "You have to learn from these experiences. (Wednesday's) experience hopefully gives them something to build on and work with. Both the negative and the positive. Everything has to be useful and serve some purpose."

Renteria is right about the learning experience. If Pedro Strop's struggles on Wednesday make him better for it than it was worth the blown save. The Cubs are playing for the future. Figuring out who fits in and where is their lone priority right now.

And finding a closer.