McCarthy called for trainers after giving up three runs in the sixth inning and was removed from the game.
McCarthy was soon removed in favor of Sergio Santos. He entered the inning with a 10-3 lead, but allowed two singles and a homer before his departure. It has yet to be revealed if McCarthy suffered an injury of was taken out merely as a precaution.
The right-hander performed well from the second through the fifth innings, allowing just one hit during that stretch. He had given up home runs to Wil Myers and Upton in a three-run first. He finished having surrendered six earned runs in five innings as his ERA soared to 5.87.
Burnett worked efficiently through his start, only running into one issue in the second inning. Burnett allowed a single to Chris Owings, who then stole second base. Tuffy Gosewich then singled to right to bring home Arizona's only run.
Burnett, who remains 0-1 on the year, lowered his ERA to 1.80 and added four strikeouts to his totals.
De La Rosa's only blemish came in the fourth inning. He allowed a double to Neil Walker, who advanced to third on a Starling Marte ground out. Then, Pedro Alvarez doubled to right field, scoring Walker.
De La Rosa, who remains 2-1, lowered his ERA to 4.68 on the season.
Another defeat for him and Milwaukee.
Peralta allowed two runs on seven hits in 6 1/3 innings against St. Louis with two walks and four strikeouts. But now he is winless in three decisions.
The outing was still encouraging considering he began the evening with a 5.68 ERA and had surrendered 10 runs on 18 hits in his previous 12 innings pitched.
Peralta cruised after allowing a two-run triple to Kolten Wong in the second. He allowed five hits the rest of the way and worked out a jam in the sixth.
He is set to start again Friday against the host Cubs.
With one out in the third, May gave up a liner to third baseman Kyle Seager, who ripped it right back to him. May tried to stay in the game, but was replaced by Tim Stauffer. He allowed two runs on three hits with five strikeouts in 3 1/3 innings against Seattle.
"Compared to my last outing, I think my command got better," Chen said to MASN Sports. "I made an adjustment, and it worked out pretty well today. In the previous outings, I wasted too many pitches and could not go this deep in the game. It was very important for me to go deep in the game and feel like the manager was trusting me to let me out there pitching."
Chen's next start is scheduled for Friday against the Rays.
The 22-year-old Gonzalez is 1-1 with a 3.57 ERA in three starts with Triple-A Lehigh Valley this season. He has yielded 20 hits and just two walks in 17 innings with nine strikeouts.
He peaked at the Class A and Double-A levels in 2013, but struggled last season at Double-A Reno with a 9-13 mark and 4.59 ERA.
Buchanan allowed three runs on two hits in six 2/3 innings of work. Things were looking up for Buchanan early, when he went six scoreless to start the game. Then in the seventh, he allowed a lead off home run to Andrelton Simmons. After getting two outs, Buchanan walked the final two hitters he faced before getting the hook.
Buchanan, now 0-4 on the year, boasts a 7.52 ERA in 20 1/3 innings this season. He will look for win No. 1 Thursday against the Cardinals.