Is a reshuffled Bruins D corps better off by splitting up Charlie McAvoy, Matt Grzelcyk?

(Staff Photo By Matt Stone/ MediaNews Group/Boston Herald)

The ice in front of and around Brandon Carlo when the 6-foot-5 defenseman is out on a shift has traditionally been where scoring chances go to die. 

During the 2018-19 season, Carlo ranked first among 87 NHL defensemen (min. 1,200 5v5 minutes) in goals against per 60 minutes of play with a rate of 1.48 — edging other defensive stalwarts such as Colton Parayko and John Klingberg, who ranked third and fourth in the same category.

A year later, Carlo’s 5v5 GA/60 rate of 1.75 ranked 10th overall among the 197 D-men with 500 minutes of ice time logged.

Of course, some of those lofty numbers are a byproduct of the stingy and fundamentally sound style of play that the Colorado Springs native thrives on — with his strong frame and long reach adept at separating player from puck and clearing biscuits out of Grade-A ice.

But make no mistake, some of those metrics are also a direct result of the unorthodox pairing that Carlo formed with Torey Krug over the last few seasons, with the balance of Carlo's stay-at-home game and Krug's puck-moving prowess — and plenty of favorable O-zone starts along the way — helping to keep Boston's second D pairing away from extended shifts hemmed in their own zone.

Well, if it ain't broke....

Although Krug is now orchestrating power plays in St. Louis, Boston doesn't appear to be deviating from the formula that has yielded so much success on their second D pairing over the previous three seasons, as fleet-footed defenseman Matt Grzelcyk appears to be the heir apparent for Krug in a variety of ways — whether it be getting the keys to the man advantage or earning regular reps next to Carlo in 2021.

With time not on the Bruins' side during this abbreviated training camp, Bruce Cassidy and the B's are committing early to a number of personnel combinations — with lines such as DeBrusk-Krejci-Kase and Ritchie-Coyle-Smith remaining intact through the first few days of Boston's on-ice work at Warrior Ice Arena. Such has been the case on a Bruins' blue line with seemingly little set in stone entering camp — with Grzelcyk and Carlo regularly skating together during multiple drills at the club's practice facility in Brighton.

Both Carlo and Grzelcyk have been sharp since the first group session commenced on Monday, with Carlo routinely plowing opposing skaters outside of the crease on 5v5 drills and intercepting feeds on 3v1 rushes as the last line of defense. Grzelcyk has been as advertised with the puck on his stick, with the 27-year-old skater excelling on breakouts and transitional play while serving as a vocal presence next to Carlo.

Even though Carlo's reps with Grzelcyk over the last three seasons (372:51 of 5v5 ice time) pale in comparison to the extensive time he logged with Krug during that same stretch (1769:22 of 5v5 ice time), there's still plenty of chemistry present between Boston's new second pairing (for now, at least).

"Brandon's a great player," Grzelcyk said of Carlo, adding: "He skates so well for how big he is and makes it a lot easier when you're playing with him to close plays quickly and get going the other way and once we're stuck in zone, he's one of the best defenders — 5v5, can PK a ton, and he takes a lot of pressure off you being his partner. He takes a lot of pride in closing plays off himself. And I think that allows me to grab pucks hopefully and get transition the other way, which is what we want to do, want to play fast. And he does that so well."

Both on paper and through the good ol' eye test, there's a lot to like about what Grzelcyk and Carlo can bring as regular D partners in 2021. But with Charlie McAvoy sitting atop the depth chart — and given the production generated when the B's new No. 1 defenseman skates with his former collegiate teammate in Grzelcyk — is this D corps really better off with those Terriers skating on separate pairs?