Muller will start Tuesday's game against the Nationals, Justin Toscano of The Atlanta Journal-Constitution reports.
Muller joined Atlanta's taxi squad Monday and will be recalled from Triple-A Gwinnett a day later to make a late-season start in the majors. The southpaw gave up nine runs in 7.2 innings over two starts for Atlanta earlier in the season, but it's possible that he also makes a start next week in Miami if he performs relatively well Tuesday.