DeRosa, a 38-year-old bench player the Blue Jays added this season for depth, has been dealing with a sore neck and a slump at the plate in which he hadn't had a hit since June 18 against Colorado.
So when an injury forced first baseman Adam Lind out of the roster, DeRosa found himself filling in Monday. Even more unexpected was his No. 4 spot in the batting order.
But no one was more surprised than the Detroit Tigers when DeRosa launched a three-run homer, an exclamation point in Toronto's 8-3 victory against the American League champions.
"I've always been a guy who likes to work the ball the other way and it's been frustrating over the last couple weeks," said DeRosa. "You know, flying open, striking out and grounding out to short. Doing things that, I pride myself on being a quality at-bat. Definitely hitting fourth was not on the agenda coming into the season."
DeRosa joked he told star Jose Bautista, who was hitting third in the lineup after slugger Edwin Encarnacion was pulled just before the game with left hamstring soreness, to take off his shin guard at the plate and expect to be walked.
It ended up being no joke at all. The Tigers walked Bautista twice, and DeRosa made them pay in the fourth inning with his fifth homer of the season.
"Obviously you can't replace Eddie, you can't replace the way Lind swung the bat. I'm aware of that," said DeRosa. "But there's guys here that are capable of doing things they have to to help us win."
DeRosa had plenty of help during a festive Canada Day game at Rogers Centre.
Shortstop Jose Reyes, who made his first appearance at home since April before he was put on the disabled list with a severely sprained left ankle, hit his second home run in two games.
Blue Jays knuckleballer R.A. Dickey (8-8), following up on his best outing of the season last week, was again solid against Detroit's intimidating batting order. He allowed two earned runs on six hits with four strikeouts through seven innings.
Two of those strikeouts were against reigning batting champion Miguel Cabrera, who is leading the majors with a .369 average. Dickey said his velocity is returning, and that's making the knuckleball much more effective than it was during a rough start to the season.
"I think any pedestrian could see that (the pitch) is harder. That the velocity's come back," said Dickey. "It's been kind of a tough go getting it back. I threw a knuckleball 81 miles an hour today, I threw a lot of 80 miles an hour, I threw an 85 mile an hour fastball. All those velocities are tops for the year."
Prince Fielder, who hit a solo homer off Dickey, said he could see why the other Tigers batters were having so much trouble.
"It was knuckling. It's hard for catchers to catch it so imagine how hard it is to hit it," said Fielder.
Dickey was relieved by Steve Delabar, who impressed by striking out the heart of Detroit's offence in Torii Hunter, Cabrera and Fielder in the eighth inning. Aaron Loup finished the game for Toronto in the ninth to get the Blue Jays (41-41) back to .500.
Omar Infante, who finished 4-for-4, went deep in the ninth for the slumping Tigers (43-38), who now have just one win in their last seven games and trail American League Central-leading Cleveland by a half-game.
"We're in a little funk right now and we've just got to get ourselves out of it," said Detroit manager Jim Leyland. You'll got to roll with that punch and you've got to try and do something about it."
Tigers rookie left-hander Jose Alvarez (1-2), making his fourth start of the season, lasted just three innings after giving up five runs, four earned, and walking three with four strikeouts.
Reyes opened a four-run third inning with a solo shot into the left-field second deck to the roar of 45,766 fans at Toronto's fifth sellout of the season.
Rajai Davis then sent a double into the same direction. Davis, who is playing every day with Melky Cabrera on the 15-day disabled list, appeared to distract Alvarez from his duel with Bautista by attempting to steal third. Davis took third before the at-bat was over and Alvarez walked Bautista.
Alvarez then walked Colby Rasmus to load the bases. J.P. Arencibia capitalized with a two-run double to bring home Davis and Bautista. Maicer Izturis then added an RBI sacrifice fly to put the Blue Jays up 5-0. Alvarez finished the inning before being replaced by reliever Luke Putkonen.
Fielder put the Tigers on the scoreboard with a home run over the right-field wall in the fourth. Victor Martinez doubled on the next at-bat and was then scored on a ground-rule double by Infante to cut into Toronto's lead by two.
DeRosa gave the Blue Jays a six-run advantage in the bottom of the inning. Davis singled then stole his second base of the game. He was followed by Bautista's second walk of the game, and DeRosa scored all three with a homer to right off Putkonen for an 8-2 lead.
The Blue Jays capitalized on a balk by Alvarez to take a 1-0 lead in the second inning. Alvarez stepped off the plate against second baseman Munenori Kawasaki, advancing Izturis and Josh Thole.
Then Kawasaki — the clear crowd favourite of the Blue Jays lineup — hit an RBI single that brought home Izturis. The inning ended however when on the same play Thole was caught at the plate.
The game was a party for the holiday crowd. Members and families of the Canadian Armed Forces held a massive flag during the pre-game ceremony while Canadian music acts such as Classified and Arcade Fire were blared over the speakers. The Blue Jays wore red jerseys and were joined on the field by the national junior baseball team for the anthems.
"It was fun. What a fun day," said Dickey. "As an American it was neat to be a part of it. It's fun to be embraced by a community any time."
Notes: Lind is day-to-day with back pain after being pulled from Toronto's 5-4 loss in Boston on Sunday. ... Encarnacion, who is day-to-day, has also been playing with a sore wrist. Manager John Gibbons said Encarnacion's wrist is hampering his ability to field but not swing the bat. He was replaced as designated hitter by Arencibia. ... Blue Jays right-hander Chien-Ming Wang (1-1, 5.24 earned-run average) faces Tigers' RHP Doug Fister (6-5, 3.50 ERA) on Tuesday. ... IndyCar driver Alex Tagliani of Lachenaie, Que., threw the first pitch.