Buchholz, who threw 45 pitches, retired the first seven batters he faced. The right-hander struck out one, walked none and worked around one-out hits in the third and the fourth. His shortstop, Pedro Ciriaco, ended the second by stabbing an Andy LaRoche liner out of the air.
Ciriaco in turn had help from Blue Jays shortstop Ryan Goins and LaRoche at third. Blue Jays starter Justin Germano, who let up two runs in three innings and threw 29 of 38 pitches for strikes, got a pop-up from Ciriaco with one out in the third and the game scoreless. The sun appeared to be a factor despite cloud cover all game.
Germano, who struck out two and walked none in his first start, said it felt good to get back on a more normal routine.
"Over the years I've learned how to get ready for the game as a reliever, but my comfort zone is definitely starting to develop," Germano said. "I've done a lot better getting into the zone and I'm comfortable doing it. At first, it was kind of a mess out there, a lot going through my head, but I've been able to slow it down having to do it more."
Three batters later, Dustin Pedroia's two-out RBI single made it 1-0. Mike Napoli, who went 2-for-3, banged one off the Monster that brought in another run.
Boston added another run for a 3-0 lead in the fourth on a Will Middlebrooks leadoff double that Ryan Sweeney, another Sox hitter who had two hits, followed with a single up the middle.
Once Buchholz exited, Negrych's hot spring continued. Batting ninth, his second homer of the Grapefruit League season came off Sox left-hander Andrew Miller, who had given up just two hits and struck out six in four innings entering the day.
Boston setup man Andrew Bailey threw a scoreless inning for the second straight appearance.
Up next: The Blue Jays are on the road again Wednesday with a 1:05 p.m. ET game against the Pirates in Bradenton. Lefty Mark Buehrle is scheduled for his fourth start of the spring, opposite Pittsburgh's James McDonald.