"I made a bad pitch trying to throw strike one," said Bass (0-1).
Toronto's Jason Frasor (4-0) pitched the 11th to earn the victory.
So a possible win became a frustrating loss for the Orioles, who have dropped the first two games of the three-game series against a team that has defeated them nine of the past 11 times dating back to last year. It was a tough way for Brian Roberts to celebrate his 1,000th game as an Oriole -- the 15th player to reach that plateau -- and for Nick Markakis to end a career-high hitting streak at 17 games.
"I felt confident we were going to close the game out," Orioles manager Dave Trembley said. "Sherrill's done it before. We didn't get it done. "
The lead lasted only until Sherrill's second pitch of the bottom of the 10th, a 1-0 fastball.
"The second pitch was down," Sherrill said. "I thought it was a pretty decent pitch. It was, but in the middle, so he was able to get extended on it [and] hit it out. Then it's just time to regroup and get the rest out."
The Orioles have lost five straight, and in each game they have held the lead at some point. Six of Baltimore's last seven losses have been by one or two runs.
"It was just a tough game for us to lose -- a good game for them to win," Trembley said. "The guys want to win -- everybody wants to win -- it just seems that every miscue that we make comes back to hurt us. And the other teams take advantage of their opportunities. Plain and simple, that's what's going on."
Sherrill allowed a single and a walk with two outs, but he escaped the 10th and preserved the tie.
"It wasn't where I wanted it, but it was still a decent pitch," Sherrill said of the ball Hill hit deep. "Down in the zone is where you want to be, but it was over the plate and he was able to handle it."
Sherrill was not the only Orioles pitcher who felt he made a good pitch that was hit by a Blue Jays batter. Bass felt Barajas' leadoff single came on a good pitch.
"They've got some good hitters," Sherrill said. "A lot of guys have made some pretty good pitches and they've handled them. They're pretty hot as a whole lineup right now. It might be a different story the next time we face them. We might throw them a cookie right down the middle and they'll pop it up. That's how the game goes."
The game opened as a matchup of inexperienced starters, with Toronto right-hander Robert Ray making his Major League debut after being called up from Triple-A Las Vegas on Friday. Ray gave up a first-inning home run to Adam Jones and two more runs on Aubrey Huff's double in the third. He left the game with two outs and one on in the sixth with the game tied at 3. Roberts, who walked with one out, was thrown out at third by Snider on Jones' single to left field for the second out of the inning.
The Orioles' Brad Bergesen, who was making his third big league start, left after six innings in which he allowed six hits and three runs, all in the second inning. Vernon Wells led off that frame with a double, and he took third on an error. Adam Lind scored him with a grounder to second base. After a single and a walk, Raul Chavez singled in a run and Scutaro singled in the third run.
Baltimore missed a chance to put Bergesen in a position to win the game in the top of the seventh inning. Cesar Izturis led off with a single against left-hander Jesse Carlson, stole second base and took third on a one-out passed ball. But Carlson worked out of it, with the inning ending as Snider made a catch on Markakis' drive to deep left-center field.
The Orioles appeared set to win in the 10th when Hill was charged with an error on a leadoff grounder by Markakis against Scott Downs. A single and a flyout put runners at the corners with one out. Pinch-hitter Ty Wigginton grounded to shortstop Scutaro, who had no chance for the double play with the runner on the move from first base. Scutaro's throw home was late. It produced a run and a lead, but it was not enough for the Orioles.