"You knew it's going to happen sooner or later," Baker said after the game. "He was on a tremendous roll."
With his command off from the get-go, Volquez (10-3) subsequently established a new set of season highs and lows. The 24-year-old right-hander's 4 1/3-inning outing was his shortest start of the year. His seven runs allowed -- five earned -- were a season high.
It also was the first time Volquez allowed more than three earned runs in any of his 16 starts this season and only the second time he's given up more than two earned runs. His streak of 12 straight quality starts ended.
The Major League leader in strikeouts with 110, Volquez did not record any, but he walked three, hit a batter and threw a wild pitch. He also threw 90 pitches in quick fashion, including 47 for strikes.
"The only thing I can say is bad day. I knew it was going to happen someday," said Volquez, who maintained the same upbeat demeanor he usually has after a win. "The only thing I can do is to try to get ready for my next start."
After Volquez issued a leadoff walk to Matt Stairs in the Toronto second inning, Scott Rolen smoked a 1-1 changeup for a two-run home run to the left-field seats and a 2-0 lead.
"He didn't have command of his fastball, and their game plan was sitting on his changeup," Baker said.
The bottom of the third began with leadoff batter Marco Scutaro being hit by a 2-2 pitch and Joe Inglett walking. On an Alex Rios routine grounder to the mound, Volquez's high throw to second base pulled Jerry Hairston Jr. off the bag. All runners were ruled safe on the error, and the bases were loaded.
After another run crossed, Lyle Overbay hit a two-run single to right field for a 5-0 Blue Jays advantage. Volquez faced only four batters in the fifth inning and gave up three doubles, including RBI hits by Wells and Rolen, before being pulled.
"It just looked like he couldn't find that [arm] slot," Baker said. "Not to make excuses, but it looked like the mound was higher than normal. It didn't look like he could make that adjustment today."
"It was a little bit hard for me tonight. It was a little high and flat," Volquez confirmed. "It was not an excuse. It was a bad day for me, and a bad night. I'll be all right."
Good mound or bad mound, Volquez knew long before his trot to the showers that it wouldn't be his night.
"I think I knew before, when I was warming up in the bullpen," Volquez said. "I threw too many strikes in the bullpen. I don't like that. It was the same in the Minor Leagues. Every time I threw too many strikes in the bullpen, in the game it doesn't work."
Meanwhile, Blue Jays starter Jesse Litsch (8-4) pitched a masterful eight innings. Litsch retired 17 of his first 18 batters and allowed three hits. In the fourth, Adam Dunn hit a one-out double to right field and advanced to third base on a wild pitch. Dunn scored on Brandon Phillips' sacrifice fly.
Although his ERA jumped from 1.71 to 2.08 after Thursday, Volquez remains the Major League leader. He's tied for second in the National League in wins. With at least two more first-half starts remaining, his bid to be named to the NL All-Star team certainly is safe.
But, on Thursday, he was far from All-Star form.
"It just wasn't Edinson today," Baker said.