After winning his first four decisions, though, McCarthy has seen his ERA jump from 3.09 to 5.58 following two straight losses and the 34-year-old needs to get back on track Wednesday night against the Chicago Cubs.
The Cubs (22-17) scored twice in the top of the ninth on doubles by Albert Almora and Addison Russell for a 3-2 victory over the Braves (25-16) in the opener of the three-game series at SunTrust Park on Tuesday after dropping a makeup game 6-5 in Chicago on Monday.
McCarthy (4-2) will be opposed by right-hander Tyler Chatwood, who has won his last three decisions after a 0-3 start with the Cubs as a free-agent addition despite continuing control issues.
Chatwood (3-3, 3.35 ERA) has walked 32 in 37 2/3 innings, but has mitigated the wildness to some extent with 38 strikeouts.
McCarthy neither normally strikes out nor walks many. It's been too many hits that has been his downfall of late.
McCarthy gave up 12 hits and a career-worst eight runs over 3 1/3 innings in a home loss to the San Francisco Giants on May 5, then 11 hits and six runs over five innings in a road defeat to the Miami Marlins on Friday.
"As a movement pitcher, you're relying on that to get some weak contact," McCarthy said. "The last two starts, a lot of it is falling in and a lot of it is finding holes. When they do hit a ball hard, it's doing some damage. I've got to find a way to mitigate all of this.
"There's some mystery in there I've got to solve that brings it back to a good place. I didn't think the quality of pitches would lead to those kind of results. I'm pretty confused right now."
Braves manager Brian Snitker is sticking with McCarthy.
"You go through some stretches where things just aren't clicking," Snitker said. "You feel good and nothing is wrong. But it's just not happening for you. You've just got to keep grinding and fighting through it."
McCarthy made two starts against the Cubs last season for the Los Angeles Dodgers and won them both, giving up only six hits over 12 scoreless innings.
Lifetime, McCarthy is 2-1 with a 1.11 ERA in five games (four starts) against the Cubs.
Chatwood, who had a 4.69 ERA and was 8-15 with the Colorado Rockies last season, has walked at least five batters in five of his seven starts for the Cubs. However, he is 3-0 with a 2.45 ERA in his last four starts.
"I know what it is," the 27-year-old Chatwood said of his control issues. "I feel it's an easy correction, but I'm fighting it now. It's just a matter of having it click. I know what it is. I'm kind of fighting it back and forth."
"I think it's delivery-related," Cubs manager Joe Maddon said. "I think he needs to find that rhythm. It's a complicated delivery. If you're not all together, you have a hard time finding your release point."
Chatwood, who signed a three-year deal worth $38 million to join the Cubs, has faced the Braves seven times (five starts) and is 2-2 with a 5.60 ERA.
Control has been an issue there as well, with Chatwood recording 20 walks in 27 1/3 innings.
Freddie Freeman is 7-for-13 for the Braves against Chatwood and has walked twice.
The only Cub with more than seven at-bats against McCarthy is Ben Zobrist. He is 6-for-24 with a home run.