Frederik Andersen vs. Tuukka Rask

Goaltending is an integral part of the Stanley Cup Playoffs. To better understand the strengths and weaknesses of each goaltender, the last 100 goals allowed for each goaltender in the regular season were charted, with the help of Apex Video Analysis and Save Review System from Upper Hand Inc., to see what patterns emerge.

RELATED: [Complete Bruins vs. Maple Leafs series coverage]
Frederik Andersen of the Toronto Maple Leafs and Tuukka Rask of the Boston Bruins will face each other in the Eastern Conference First Round for the second straight season.
Though Rask and the Bruins won in seven games last season, neither goalie fared particularly well; Rask had an .899 save percentage in the series and Andersen was at .896, numbers that reflected the ability of each team to take advantage of specific style habits of the opposing goalie.
Andersen has focused on being less predictable and harder to pre-scout this season. The ability for each to limit their past exposures could play a role in deciding the winner when the best-of-7 series begins with Game 1 at TD Garden on Thursday (7 p.m. ET; NBCSN, CBC, SN, TVAS, NESN).
Here is an in-depth look at each goalie's game:

Frederik Andersen, Toronto Maple Leafs

Andersen (36-16-7) finished tied for third in the NHL in wins this season and was cruising along as a likely Vezina Trophy finalist before a late-season dip dropped his save percentage from .924 to .917. Though he didn't get much help from his defense, Andersen had an .881 save percentage in his final 10 games of the regular season, and how long he gets to keep playing in this series could depend on his ability to correct some of the issues he and his defense faced.

Goal Trends

Clean off rush: If there was a trend in the late-season slide that seemed to be most alarming, it was the number of times Andersen was beaten clean off rush chances, and the numbers back up this concern. Andersen was beaten 30 times on clean shots where he had time to be set on the shooter, one of the few goal attributes he was worse than the average (22.9 percent) and a notable increase from the 17 he allowed in the 100-goal sample to end last season. Eleven of those goals came since March 1, and if there was a tendency evident in most of them, it was a widening of his stance early in a shot-release sequence. When at his best, Andersen is cutting pucks off in front of him and moving into shots. When he locks in wider and lower, it gets harder to move laterally. A resulting tendency to sink or sit down in his stance left him prone to pulling back with the shoulders and trying to play catch-up behind him with his hands when dealing with high shots. Delaying or changing the angle of the release seemed to allow shooters to catch Andersen in this transition and beat him clean more often late in the season, even from as far away as the top of the face-off circles.
Low-high less successful: Andersen always has employed a variety of goal post-integration tactics, but a renewed focus on being efficient in each of them seems to have paid off. He is more comfortable when play didn't allow for perfect execution of his preferred method as well. After being beaten 29 times on low-high passes or plays originating near or below the goal line last season, Andersen gave up 19 goals on low-high plays this season, closer to the 17.4 percent average for the 5,500 goals recorded for this project during the past three seasons.
Against the grain: For the second straight season, Andersen was above the tracked 16.9 percent average for shots or plays that caught him moving one way when the puck beat him in the other direction. Last season it was 22 percent; this season it was 25 percent. In part, that percentage reflects how often the Maple Leafs give up chances that force him to move laterally: 46 of Andersen's 100 goals in this study came on plays across the slot line, an imaginary line that splits the offensive zone in half from the goal line to the top of the face-off circles. This is well above the 35.5 percent average.

Tuukka Rask, Boston Bruins

Rask (27-13-5) posted his lowest win total in six seasons and lowest save percentage (.912) of any of his full seasons in the NHL, but he also played the fewest games (46) in a full season since becoming the Bruins' No. 1 in 2012-13. Boston is hoping the extra rest helps its 32-year-old starter, who had a .913 save percentage from Jan. 1 on. If not, it's easy to wonder how long his leash will be after backup Jaroslav Halak finished his first season in Boston among the NHL leaders in several statistics, including a .922 save percentage which ranked ninth among goalies who played at least 30 games (Rask was tied for 25th), and a 2.34 GAA, which ranked seventh (Rask was 11th at 2.48).

Goal Trends

Rotation in zone, flat off the rush: Rask has done a good job of improving his lateral movement on end-zone play through his career, taking some of the open-and-close delays out of his side-to-side movements, including a tendency to back into plays to his right. Last season he got caught sliding across on his knees on lateral plays he used to beat on his skates. That wasn't as noticeable this season. He still is prone to his old backward flow patterns off the rush, including a tendency to retreat parallel to the goal line, which can leave him off angle on plays down the wing and accounted for some of the increase in clean-shot goals allowed, 23 this season after 14 last season.
Post play: Rask has modernized his post-integration habits during the past couple of seasons, using his back leg more to pivot around and move off his posts from reverse-VH, a technique where he anchors the post with his short-side pad along the ice and keeps the back skate engaged. In doing so, he's at least reduced, though not eliminated, a tendency to go into the posts with the shin of his pad and bump off with a narrow butterfly that limited coverage along the ice. His goal totals on low-high plays were up to 16 this season from 12 last season, but still down from 21 two seasons ago, when his post play was more predictable. Toronto beat him three times in reverse-VH last year, including two over the shoulder on the short side, a spot that can be targeted when he drops into reverse-VH with the puck near the bottom of the face-off circle.
Stretch him out: Rask's goals allowed on lateral plays across the slot line were down from 50 last season to 34 this season, but without shot totals and a save percentage for these types of plays it's hard to tell how much of that was based on the quantity of those chances he faced. He still tends to start outside his posts on rush chances, increasing the distance to cover on cross-ice passing plays, and the Maple Leafs successfully pulled him wide during the playoffs last season, which tends to leave him extended, off balance and falling forward rather than pushing across.