The St. Louis Cardinals haven't been swept on the road all season and haven't been swept in Atlanta in more than 10 years.
St. Louis (62-39) leads the league with 496 runs but has scored one through the first two games of this set. The Cardinals' six hits over consecutive games are their lowest total for an offense batting an NL-best .275.
Yadier Molina's second-inning homer in Friday's 4-1 defeat has been followed by 16 scoreless innings at the plate. Julio Teheran and two relievers combined on a two-hitter in Atlanta's 2-0 victory on Saturday.
The Cardinals have dropped four straight in the regular season at Turner Field, where they won 6-3 in last year's NL wild-card playoff - a loss that still stings for the Braves.
"They're a great team," shortstop Andrelton Simmons said. "They got us last year in a pretty big game. We owe them some. It's good to see this team beating them."
Medlen (6-10, 3.78 ERA) was the starter for Atlanta (59-45) in the wild-card defeat, allowing five runs - two earned - over 6 1-3 innings. He gave up a homer to Matt Holliday - activated off the disabled list Saturday - in his first start of any kind versus St. Louis.
The right-hander has posted an 8.59 ERA in dropping three straight starts for the first time in his career.
Medlen has received two total runs of support during his slide. His average of 3.40 is one of baseball's lowest marks.
He will be opposed by Shelby Miller (10-6, 2.77), who has never faced the Braves. The Cardinals were happy with Miller after the 22-year-old returned from a 12-day break with six scoreless innings in Tuesday's 4-1 home win over Philadelphia.
Miller had given up 10 earned runs in 12 2-3 innings over his previous three starts.
"The biggest thing for me was to clear my head and get back to where I need to be," Miller said. "I just relaxed and threw out there. I got some time away, got time to work on some mechanics and get things straightened away."
Now the right-hander will try to improve on the road, where he has a 4.07 ERA compared to a 1.74 mark at home.
Atlanta is in position for its first three-game home sweep of St. Louis since April 22-24, 2003, but the Braves' offense has actually produced fewer extra-base hits in this series. The Cardinals have five and Atlanta four.
One of those hits for the Braves was Simmons' two-run double in the eighth inning Saturday. Chris Johnson is 4 for 6 in this series for Atlanta.
The Cardinals' Carlos Beltran is hitless in his last 11 at-bats and 1 for 9 overall against Medlen. Molina's homer Friday is his only hit in his last 10 at-bats, while fellow MVP candidate Allen Craig has gone hitless in three straight games for the first time in 2013 with nine empty at-bats.
This series features four of the league's top hitters in Molina (.332), Johnson (.332), Craig (.329) and Matt Carpenter (.321).