The Blue Jays took two out of three from New York after losing 12 of their first 13 meetings this season. They're 3-3 against the Yankees at home and 0-10 on the road.
Kuroda (11-10) lost for the fourth time in five starts and gave up seven runs for the second straight outing, matching his career high for the seventh time. Five of the seven runs off Kuroda were earned. He allowed nine hits, walked one and struck out four.
"The movement of my balls is not there as before," Kuroda said through a translator. "I've been hit squarely. There are cases where I jam them and it ends up being a single."
Kuroda lost just once in nine starts between June 13 and July 31, then went 1-4 in five August starts.
"To not have my stuff at this stage of the season is pretty frustrating," Kuroda said.
Catcher Chris Stewart said Kuroda was better against Toronto than in his previous start at Tampa Bay, where he gave up seven runs and four homers in six innings.
"He's just making bad pitches every once in a while and they're not missing them," Stewart said. "Today he wasn't overly bad, he was better today than the past couple of ones."
Kuroda came in 4-0 with a 1.60 ERA over his previous five starts against the Blue Jays, but couldn't bring an end to his recent road struggles, falling to 0-4 with a 6.94 ERA in his past four starts away from home.
"He's struggling a little bit right now," Yankees manager Joe Girardi said. "We need him to turn it around and I believe he will his next start."
Girardi acknowledged that continued struggles by Kuroda and right-hander Phil Hughes, who is winless in nine starts, will make it "really, really hard" for the Yankees in their chase for a wild card berth.
New York is 19-19 since the All-Star break, and has lost 10 of 15 road games in August.
"Any loss at this point in the season is rough on us," catcher Chris Stewart said. "Time is ticking away and we don't really have much room for error."
Redmond (2-2) left to a standing ovation after striking out Alfonso Soriano and Alex Rodriguez to begin the sixth inning. He allowed two runs and three hits, walked four and struck out seven for his first victory since beating Minnesota on July 7.
"He's got a little deception to him because of his arm angle," Girardi said of Redmond. "Sometimes his fastball runs, sometimes it goes up, his slider was pretty good tonight."
Yankees second baseman Robinson Cano was held out of the lineup, one day after being hit by a pitch on the left hand. Manager Joe Girardi said Cano was still dealing with pain and swelling, but said he hoped to have the five-time All-Star back for Friday night's game against Baltimore. The Yankees are off Thursday.
New York's Eduardo Nunez, who left Tuesday's game with a sore right knee, was scratched from the lineup after he felt sore during batting practice. Mark Reynolds made his first career start at second.
"He couldn't run full speed," Girardi said of Nunez, who will undergo an MRI on Thursday.
Toronto took advantage of a throwing error by Stewart in a four-run, two out rally in the first. Brett Lawrie hit a two-run double and Rajai Davis was hit by a pitch before J.P. Arencibia reached on a two-strike passed ball. Lawrie and Davis both scored when Stewart's errant throw to first rolled into foul territory down the right field line.
"I called a slider and he threw a fastball," Stewart said. "I was expecting it to break down and away and it just stayed right over the middle of the plate and went off my glove. I tried to force the issue after that, I probably should have just eaten the ball."
The Blue Jays made it 6-0 when Encarnacion clubbed his 34th home run in the second, a towering two-run shot to left. A seventh run scored on Jose Reyes' sacrifice fly in the third.
Redmond said he appreciated the cushion provided by his offense in the first two innings.
"It gives you a lot of confidence," he said. "To come out with an early lead enables you to throw strikes and get ahead of hitters."
New York broke through against Redmond in the fourth, when Rodriguez hit an RBI single. One out later, Reynolds hit an RBI double, but Rodriguez was thrown out at the plate trying to score from first.
Rodriguez finished 1 for 4 with three strikeouts.
The Yankees struck out 13 times, one shy of their season high for a nine-inning game. ... Girardi said Hughes remains on track to make his next scheduled start Sunday. Hughes has not won since July 2 at Minnesota. ... Toronto RHP Steve Delabar (shoulder) threw one perfect inning for the Gulf Coast Blue Jays on Wednesday, his first rehab appearance.