The Maple Leafs  got goals in the first and second periods from Nazem Kadri and Mikhail Grabovski, respectively. Frazer McLaren made it 3-0 early in the third when he took a loose puck in front of the net and backhanded it off his skate and through the five-hole of Khudobin. The goal chased Khudobin in favor of Tuukka Rask , as Claude Julien  replaced his starting goaltender for the first time this season. Khudobin, who was starting his second consecutive game for the first time this season, allowed the three goals on 11 shots.
Dennis Seidenberg  got the Bruins on the board with a wrist shot from the point following the goalie change, with Andrew Ference  scoring to make it 3-2 with the goalie pulled and just over a minute to play.
The Bruins outshot the Leafs, 33-13. The loss was the Bruins’ first against the Maple Leafs since March 19, 2011, breaking up a string of eight consecutive wins against Toronto for the B’s.
With their four-game road trip concluded (1-3-0), the Bruins will return to Boston and host the Leafs Monday at TD Garde
WHAT WENT WRONG FOR THE BRUINS
– With the Bruins down two of their six defensemen in Adam McQuaid (shoulder) and Johnny Boychuk  (leg), Claude Julien  had to rely more on his other blueliners. Andrew Ference  led the B’s in time on ice through two periods (16:59) as Julien played Dougie Hamilton (8:09 through two periods) more sparingly. Hamilton did come up big by swatting a puck out that was headed into the net after a Khudobin save on a Toronto 2-on-1, but Julien clearly had his younger defensemen on a shorter leash Saturday.
– Speaking of defensemen, Bartkowski had a forgettable night in his season debut. The 24-year-old was on the ice for Toronto’s first two goals, the second of which was the result of a play that started with the youngster pinching in the offensive zone. With Bartkowski pinching, Toronto was able to get the puck out of the zone, and though Milan Lucic  was back, Grabovski was able to blow past him with ease.
– Bartkowksi and Lucic weren’t the only two who deserved blame on the Grabovski goal. The Toronto forward was struggling with the puck from the right circle, and David Krejci  had both time and the opportunity to take the body or steal the puck, but he allowed Grabovski to regain control of the puck and fire a shot past Khudobin to make it 2-0.
– The Bruins turned it on following an Aaron Johnson high-sticking penalty in the first period, and the closest they got to scoring was on a shift by the David Krejci  line. Nathan Horton  had two golden opportunities to tie the game, but couldn’t bury it. Horton had James Reimer off-guard when the right-winger controlled a loose puck in front but fired a low shot right into the Toronto goaltender’s pads.
– The Bruins were putting the pressure on heavy after Seidenberg got them on the board, but a power play in which they got zero shots on goal halted any momentum the B’s may have gained to that point.
WHAT WENT RIGHT FOR THE BRUINS
– Though they got nothing to show for it, the Gregory Campbell  line was once again Boston’s third line and came out of the first period with two of Boston’s better shifts in the first 20 minutes. Daniel Paille  failed to bury chances on both shifts, but give the Merlot Line — including Shawn Thornton , who dropped the gloves with Colton Orr after Toronto took a 1-0 lead — credit for showing up in an increased role.
– Seidenberg’s goal was his second in as many games, which is pretty impressive when you consider that he had no goals on the season entering Thursday.