But unlike Brandon Morrow, who had to leave Wednesday's win over Baltimore after taking a liner to the right leg, Henderson Alvarez was able to continue.
The right-hander recovered after being struck in the left leg on a ball off the bat of Mike Aviles in the fifth inning, but was unable to tame the Boston offence as the Red Sox defeated the Blue Jays 7-2.
"That one hit him pretty square too," Arencibia said of Alvarez, who ended up going 6 1-3 innings after getting attention on the field. "You don't want to see that two games in a row — a ball back to the pitcher. Fortunately enough he was OK."
Other than the Aviles' shot off his leg, the night was a forgettable one for Alvarez (3-5), who gave up four runs on eight hits, including a home run by David Ortiz.
Ortiz and Adrian Gonzalez each drove in two runs and Clay Buchholz pitched eight strong innings for the Red Sox.
Buchholz (5-2) struck out seven in holding the Blue Jays to six hits and just two runs — each coming on solo homers by Yunel Escobar and David Cooper.
The win in the opener of a three-game series gave the Red Sox (27-25) their 15th victory in their past 21 outings. It also ended the Blue Jays' three-game winning streak, leaving the teams tied at the bottom of the American League East.
But the most important thing for Toronto (27-25) is that for the second game in a row the club had a starter avoid serious injury after being struck by a hard-bit ball.
"Henderson kept us in the ballgame," Blue Jays manager John Farrell said. "He didn't feel any ill effects from the ground ball off the shin, stayed in it."
Buchholz, meanwhile, has won each of his six starts in Toronto dating to July 17, 2009.
"I just didn't have the inning where I couldn't shut them down without scoring three or four runs in that one inning so it sort of came together tonight," Buchholz said. "I was able to get some weak contact in some big situations, get some big double plays in some big situations and the guys went out there and hit and put up some runs. I was able to work with it tonight."
Buchholz is the first pitcher to beat the Blue Jays six in successive starts in Toronto.
"He commanded the ball well, he cut the ball away from us a lot," Arencibia said. "He made some good off-speed pitches and kept us off balance and off the heater."
Farrell coached Buchholz in Boston and said the righty was tough all night.
"Four pitches for strikes," Farrell said. "Good stuff. After about the third inning he got into a much better rhythm and groove. He would drop down occasionally with his curveball which is something we haven't seen from him for a couple of called strike threes."
The Red Sox have been waiting for a performance like Friday's from Buchholz.
"He's been building to that, that's for sure. Clay Buchholz was terrific tonight," Boston manager Bobby Valentine said. "Extra on his fastball, terrific change-up, changed his angle a little on his breaking ball, threw strikes, very competitive. I like that, he likes that and I expect we can get more of the same."
Ortiz led off the second with his 13th homer of the season in 10-pitch at-bat.
Boston took a 2-0 lead in the third on Daniel Nava's double, his first of three doubles in a four-hit game, and a single by Gonzalez.
The Blue Jays got one back with two out in the third on Escobar's third home run of the season.
Alvarez recovered from the shot off the leg in the fifth to get two ground balls to second, the first leading to a double play.
The Red Sox loaded the bases with none out in the sixth on a single by Nava, a double by Gonzalez and a walk to Ortiz. Jarrod Saltalamacchia's grounder to first forced Gonzalez at second, allowing Nava to score. Alvarez limited the damage by inducing a double play grounder from Will Middlebrooks.
The Red Sox took a 4-1 lead in the seventh after Ryan Sweeney's leadoff double.
Left-hander Luis Perez replaced Alvarez with one out. A groundout put Sweeney at third and he scored on a Scott Podsednik infield single.
Nava then doubled Podsednik home before scoring on a single by Gonzalez, who advanced to second on the throw. Ortiz singled Gonzalez home on a line drive to right to make it 7-1 but the Red Sox designated hitter was thrown out after making the turn to second.
Cooper, playing his seventh game since being called up from triple-A Las Vegas hit his first homer with two out in the seventh.
Notes: Attendance at Rogers Centre was 29,678. ... Vladimir Guerrero will join triple-A Las Vegas on Saturday after hitting .450 with four home runs and eight RBIs with the Jays' single-A team in Dunedin, Fla. He will work in left field as well as play DH with Las Vegas. ... Boston gave third baseman Kevin Youkilis a planned day off on Friday. ... Blue Jays centre-fielder Colby Rasmus extended his hitting string to his season-best eight games with a single in the fourth. ... Boston second baseman Dustin Pedroia remained out of the lineup after coming out of Monday's game if the fifth inning with a jammed right thumb. ... Kyle Drabek (4-5, 4.55 earned-run average) will start for Toronto on Saturday in the second game of the series. Boston will counter with Felix Doubront (5-2, 3.86 ERA).