PHOENIX — Ever since they drafted him in 2009, the Rockies have felt that left-hander Rex Brothers had the stuff to be a closer. He isn’t pitching in the ninth inning yet, but he’s as close as you can get without being there.

As in one inning away.

Rockies manager Jim Tracy was careful not to overwhelm Brothers with responsibility after his arrival from Triple-A Colorado Springs. But seven weeks into his career, Brothers has earned enough trust from Tracy to work his way into the mix in the eighth-inning setup role.

“I’ve gained much more confidence in him,” Tracy said. “At some point in time, you remove the reins, take them to the trough and see if they’re going to drink the water.”

Brothers hasn’t gone thirsty lately. He has worked 12 2/3 innings in his last 15 appearances, allowing one run, eight hits and striking out 20. He has been very good vs. lefties (8-for-30, .267), but even better against right-handers (7-for-36, .194).

The last six of those appearances have come in the eighth inning, and it’s not going to stop. Brothers will set up Huston Street along with Matt Lindstrom and Rafael Betancourt, who is back in the equation with six straight scoreless innings, during which he struck out 10 hitters in 5 1/3 innings.

“It’s confidence and a comfort level,” Brothers said. “It’s a different ballgame up here and I feel like I’m getting settled in. That’s the reason things are going the way they are. They’re not always going to be this way, but I’m just going to keep it on an even keel, keep digging.

“I’ve been getting ahead of hitters and that’s what this game is all about. This is probably the best I’ve felt since I’ve been here, no doubt about that.”

Brothers was a sandwich pick, the 34th overall, in 2009 and has been on a fast track to the majors ever since. He throws 95 and 96 mph with a heavy slider that’s been nearly unhittable in recent weeks.

“The fastball command has been lights out,” Tracy said. “The slider is what it is — really, really hard to hit, whether you’re standing on the right or left side of the plate. There’s no question he can be very, very special.”

Footnotes.

Brothers began July with a 3.86 ERA but has whittled it down to 2.55. . . . The Rockies’ eight runs Friday night matched the total for their four-game series in Atlanta before the all-star break. . . . Ty Wigginton’s two-run, fourth-inning single gave him six RBIs in July in 55 at-bats. He went into Saturday’s game hitting .208-0-4 in July after .262-8-18 in June. . . . The Rockies played their 100th game of the season Friday. How inconsistent have they been? Here’s their record in 25-game segments: 17-8, 7-18, 14-11 and 10-15.