MILWAUKEE -- The Brewers promoted pitching prospect Josh Hader to Triple-A Colorado Springs, assistant general manager Matt Arnold announced prior to Wednesday's game against the A's.

Hader, the Brewers' No. 4 prospect by MLBPipeline.com, is third in the Minors with a 0.95 ERA and a WHIP of 1.00 in 11 starts for Double-A Biloxi and was named a Southern League All-Star just hours before the announcement. He has not allowed more than one earned run in any of his starts and has 73 strikeouts to only 19 walks in 57 innings.

With the left-hander joining the Triple-A Sky Sox, Milwaukee's two top pitching prospects are now just one level away from joining the Brewers. Right-hander Jorge Lopez, the team's No. 3 prospect, is the other top arm, but has been inconsistent with a 1-4 record and 6.04 ERA this season in Colorado Springs.

Hader, 22, came over to the Brewers as a part of the deal with the Astros last July. Milwaukee received Hader, Domingo Santana, Brett Phillips and Adrian Houser in return for Carlos Gomez and Mike Fiers.

Hader is among the top Minor League pitching performers this season, Santana is Milwaukee's starting right fielder with a .347 OBP and Phillips and Houser are ranked as the organization's No. 2 and No. 17 prospects, respectively. Meanwhile, Gomez is batting .190 with a .549 OPS while battling injuries and Fiers has a 5.00 ERA and 1.350 WHIP in 11 starts for Houston.

With the promotion, Hader continues his ascension to prominence as a prospect. Following last season, he pitched for the Surprise Saguaros of the Arizona Fall League and was named to the league's Top Prospects Team as he went 2-0 with a league-best 0.56 ERA in seven games.

Curt Hogg is a reporter for MLB.com based in Milwaukee.