Rex Brothers gave up four singles and a walk and exited the eighth inning without retiring a batter on Wednesday night. (AP)

DENVER -- Rockies left-handed reliever Rex Brothers tries to keeps things in perspective. But it's not easy.

This was supposed to be Brothers' breakout year. But it hasn't been.

When Colorado signed free agent LaTroy Hawkins, and shortly thereafter said he would open the season as the closer, Hawkins was quick to add, "I'm just keeping the seat warm until Rex is ready."

He isn't, yet.

When will Brothers be ready? Time will tell.

The Rockies have a numbers of concerns. Carlos Gonzalez was placed on the disabled list with a left index finger before Wednesday night's matchup with the Arizona Diamondbacks at Coors Field, and starting pitcher Jordan Lyles suffered a broken left middle finger on a tag plate in the first inning of Colorado's 16-8 loss. That will make it four Rockies on the DL with hand injuries.

It started with left-handed starting pitcher Brett Anderson, who broke his left index finger back on April 13, when he hit a Matt Cain slider off the end of his bat. And then, two weeks ago in Atlanta, third baseman Nolan Arenado fractured the middle finger of his left hand diving head first into second base. That's 40 percent of the starting rotation and two potential All-Star hitters missing from the active roster with hand injuries, and then there is starring pitcher Tyler Chatwood, who has a right elbow strain that put him on the shelf on April 30.

But those injuries will heal. The Rockies just have to be patient. They know each of them are going to get better.

Things aren't as easy for Brothers.

Bad got worse for Brothers on Wednesday night. The Rockies had put together a four-run seventh inning at the expense of D-backs relievers Joe Thatcher and Brad Ziegler in the bottom of the seventh to take an 8-5 lead. Manager Walt Weiss went to Brothers to open the eighth.

The lineup seemed perfect. Four of the first five D-backs hitters were left-handed, starting with rookie callups David Peralta, who arrived from Double-A Mobile on Sunday, and Ender Inciarte, a May 2 addition from Triple-A Reno.

Five batters, 15 pitches, four singles and a walk later, Brothers gave way to Nick Masset, and the D-backs were en route to a six-run inning and an 11-8 lead. His ERA rose from 3.76 to 5.47. And one of the more popular players among teammates, media and fans walked off amid a chorus of boos.

Brothers has become the target for the emotional responses from fans for a bullpen that has been singled out in recent days, as the Rockies went from back-to-back walk-off wins and a 26-20 record on May 20 to losing 10 of the last 12 games. Losses the last two nights to Arizona also ensured Colorado will not win its eighth consecutive home series.

Rockies relievers have made 48 appearances in the last 12 games, compiling a 6.10 ERA over 48 2/3 innings. Boone Logan and Hawkins have blown the team's only two save situations. Brothers? He has now given up 10 runs in his last 7 1/3 innings, and has pitched in nine of the last 12 games.

"We're human beings, so definitely there's disappointment," said Brothers. "You go out there to succeed."

More often than not, Brothers has succeeded. He was All-Conference at David Lipscomb University, and was selected by Colorado 32nd overall in the 2009 First-Year Player Draft. Brothers set records for Rockies relievers in 2013 with a 1.74 ERA and 32 consecutive scoreless appearances at one stretch.

Brothers converted 19 of 21 save opportunities last year, assuming the closer role after Rafael Betancourt was sidelined by a torn elbow ligament and Tommy John surgery. And he went into the offseason with the expectation he could build off that success in 2014.

If only things were that easy.

Brothers, instead, finds himself in the most challenging position he can remember facing. He tries to be philosophical.

"I don't want to let baseball define me as a person," he said. "It's a game. It is what it is."

But the struggles eat at Brothers.

"We love this game because we love to compete. We love to face a challenge and handle it," he said. "We play this game to succeed. You don't accept anything less."

Brothers thinks back an hour or so to the effort against Arizona, and the disappointment is apparent in his face.

Eight of Brothers' first 10 pitches were strikes. Four of them, however, were hit for singles, including a 1-2 pitch up and in that Didi Gregorius was able to slip into left field. And then came the five-pitch, bases-loaded walk to Gerardo Parra.

"Even if I missed on that pitch [to Gregorius], normally he would have fouled it off," said Brothers. "Baseball is baseball. You have to stay the course. The best part is we play 162 games."

He paused.

"Every guy in here, win or lose, continues to compete," said Brothers.

Brothers hasn't given up. He has, however, certainly been challenged.