Harang will take the mound for Atlanta in Tuesday night's home opener as the Braves take on the Mets and celebrate the 40-year anniversary of Hank Aaron's 715th home run.
Atlanta (4-2) signed Harang on March 26 with Kris Medlen, Mike Minor, Brandon Beachy and Gavin Floyd all on the disabled list, and the veteran right-hander paid immediate dividends Wednesday in Milwaukee.
Harang, whose 5.40 ERA last season was the fourth-highest among the 107 pitchers to work at least 140 innings, didn't allow a hit until a leadoff single in the seventh inning of a 1-0 win.
''It's a huge pickup for us,'' third baseman Chris Johnson said. ''We were struggling with having guys go down and we're going to struggle getting guys healthy and to have a performance like that, it's just what we needed."
Harang went 0-1 with a 3.52 ERA in four starts for the Mets (2-4) after they purchased his contract from the minors Sept. 9. He's 4-4 with a 5.66 ERA in 10 starts against New York and is happy he's getting to start the home opener.
"You definitely get excited to pitch in front of that kind of crowd," Harang told MLB's official website. "You want to give the fans reason to keep that adrenaline going."
The fans will likely already be pumped up after the pregame ceremony to honor Aaron's record-breaking homer. In old Atlanta-Fulton County Stadium on April 8, 1974, Aaron broke a tie with Babe Ruth when he went deep against the Dodgers' Al Downing.
"It means an awful lot to me,'' the 80-year-old Aaron said. ''I'm not one to go around bragging about certain things. I played the game because I loved the game. ... I am quite thrilled that people say that he, whatever he did, should be appreciated. That makes me feel good.''
The Braves were feeling good on a four-game winning streak before losing 2-1 to Washington on Sunday.
''In both losses, (we've) only given up two runs - 2-0 in Milwaukee (on March 31) and 2-1 here,'' manager Fredi Gonzalez said. ''But that's just the way it goes. The offense will pick it up I'm sure down the road someplace. There will be a stretch where our pitching staff is going to need our offense to pick it up.''
Colon didn't get much help from his offense in his Mets debut on Wednesday, a 5-1 loss to the Nationals. He went six innings and gave up three runs and nine hits, while New York totaled three hits.
The right-hander is 3-0 with a 1.57 ERA in three starts against Atlanta, but they all came in 2002 when he was with Montreal. Braves outfielder B.J. Upton has seen plenty of Colon, going 7 for 23 with a homer, double and triple, but he's off to a 3-for-25 start with 11 strikeouts.
Harang has been hit hard by three of his teammates from last season, with David Wright going 11 for 21 and Daniel Murphy and Ruben Tejada each going 4 for 11.
Those three combined to go 0 for 10 with four strikeouts Sunday as the Mets failed to complete a three-game sweep of visiting Cincinnati with a 2-1 loss.
Catcher Travis d'Arnaud went 0 for 3 and is hitless in 15 at-bats with six strikeouts.
''There's no easy answers here,'' manager Terry Collins said. ''The only way you do it is grind it out and have an approach, stick with it.''