After the additions of TJ Brodie and @Zach Bogosian helped shore up a much-maligned Leafs defensive unit during the shortened 2020-21 season, Toronto’s blue line has once again been a point of consternation through the first half of the 2021-22 campaign.

Even with @Morgan Rielly playing the best hockey of his career and Brodie locking things down beside him on the team’s top pairing, head coach Sheldon Keefe has been left searching for answers to Toronto’s defensive struggles for much of the season.

Many of those struggles have stemmed from the Leafs’ supposed shutdown pairing of @Jake Muzzin and @Justin Holl as both players have dealt with injuries and inconsistent play throughout the first half. Muzzin was arguably Toronto’s best defenceman in 2020-21, joining forces with Holl to shoulder the heaviest workload on the team all season long, but they have been unable to produce the same kind of results so far this season.

An illness derailed Holl early in the season and he ended up watching five straight games as a healthy scratch, paving the way for @Timothy Liljegren to establish his place in the Leafs’ defensive rotation. Compounding one problem with another, Muzzin was facing his own individual struggles for much of the season before hitting the injured list with a concussion in mid-January. While Holl has started to find his game as of late, having the aging Muzzin overcome mounting injury troubles to return to his previous form is no sure thing.

That brings us back to Liljegren and his defensive partner for much of the season in @Rasmus Sandin.

There was little question entering the season that Sandin would play a regular role in the Leafs’ lineup but Liljegren’s place on the depth chart offered less certainty back in October. Following a strong 2020-21 season with the Marlies, it appeared he had outgrown the AHL but questions regarding his ultimate NHL upside persisted.

With Holl struggling early on and @Travis Dermott failing to take a step forward in his fifth NHL season, Liljegren’s strong play on the third pair was a positive development. Through the team’s first 30 games this season, Sandin and Liljegren were tops among all Leafs’ defenders in xGF% – albeit in semi-sheltered third pairing minutes.

Though their numbers have mostly remained solid in the last few weeks, they have taken a bit of a step back, coinciding with a few more rough moments on the ice than we saw from them through the first three months of the season. It is important to note, however, that Sandin has taken on a larger role alongside Holl in Muzzin’s absence and hasn’t looked particularly out of place playing top-four minutes. Some might even argue that Sandin has played a part in Holl’s recent rebound.

At his mid-season media availability on Sunday, general manager Kyle Dubas said, “We have two young players that are playing a nightly role in Sandin and Timothy Liljegren, and playing those roles at that age, they’re going to have their ups and downs. So how do they come through it, and what are they?”

Sandin and Liljegren have both taken advantage of their opportunities so far this season, but Dubas wants to see more before deciding how to proceed ahead of the March 21st trade deadline.

“In terms of potential, those young guys probably have more than anyone else in our system, but what will they be able to accomplish here with a little bit more runway, and what can we learn from them that can be instructive for us in terms of how we want to approach the deadline with them?”

Just a month and a half away from the trade deadline, there is still plenty of uncertainty surrounding the Leafs’ defensive unit.

Will Muzzin be able to shake his first-half struggles and stay healthy? Will Holl be able to maintain his recent run of solid play? Just how much can Sandin and Liljegren be trusted to handle? Where does Dermott factor into all of this?

Ideally, the Leafs would have a much better idea of where they stand at this point of the season but Dubas and his staff plan to utilize all the time they’re afforded to assess both their needs, as well as their options.

“In terms of what we’re going to do and whether we’re active or not, I certainly think we want to take as much time as we can and use that to our benefit before deciding to do anything,” said Dubas.

Getting Muzzin back up and running will be near the top of the priority list but continuing to provide Sandin and Liljegren with opportunities to grow and gain experience will also be an area of focus. As Dubas said on Sunday, there are sure to be growing pains throughout that process, but while the Leafs can accept those growing pains when assessing their play in February and March, they won’t be afforded that luxury when playoff time rolls around.

As was the case coming into the season, Sandin seems like a safe bet to be a regular in Toronto’s playoff lineup. What kind of role he is trusted with will have as much to do with Muzzin’s play down the stretch as his own, but it is difficult to imagine that saddling the soon-to-be 22-year-old with top-four minutes in the playoffs will be Sheldon Keefe’s first choice.

For all of Sandin’s abilities, his lack of size and average at best foot speed have led to difficulties handling heavy forechecking teams at times and Keefe will likely look to shelter him a bit more than he has throughout the regular season. That said, Sandin has shown that he can make a positive impact chewing up third pair minutes and has filled in admirably since Muzzin was forced out of the lineup. He is a play-driver on the third pair who can step into a bigger role in a pinch but the numbers show that he is probably best suited as a number five or six defenceman at this point in his career.

PuckIQ.com breaks down players’ ice time into three separate categories based on level of competition; elite, middle, and gritensity. Yes, gritensity. Using their Dangerous Fenwick For (DFF%) measure, which tracks high-danger unblocked shot attempts for and against, we get an idea of how well Sandin has driven play against varying levels of competition so far this season.

Not surprisingly, Sandin has been far more effective against lesser competition but his numbers against elite competition are respectable for a player as inexperienced as he is. Combine that with the fact that Muzzin’s DFF% ranks below his against all levels of competition, and the door is open for Sandin to grab hold of a larger role if Muzzin isn’t able to turn things around upon his return to the lineup.

Liljegren’s play has had a few more peaks and valleys than Sandin’s as the young Swedes navigate their first full NHL seasons together. He doesn’t possess the same instincts or offensive upside that Sandin does, but has suffered from a lot of the same issues.

Still adjusting to the sheer pace of the NHL game, Liljegren has been victimized on occasion by rushed decisions or slow reads. There will have to be a noticeable improvement in that area of his game over the next few weeks in order to convince Dubas and Keefe that they don’t require reinforcements on the back end, and he’ll still be competing for minutes with Dermott at the same time.

Dermott has been an above-average third pairing defenceman for almost his entire NHL career but just hasn’t been able to take that final step towards becoming a bonafide top-four defender. At this point, it appears that he has been surpassed by both Sandin and Liljegren, at least in terms of earning another look in the top-four.

As it stands, the Leafs blue line is made up of a strong top pairing in Rielly and Brodie, two second pairing guys who haven’t played that way this year in Muzzin and Holl, and three younger players with top-four potential who are varying degrees away from being that just yet.

It feels like an addition to the Leafs’ blue line is imminent, but the way the group handles their business in the lead-up to the trade deadline will help influence what direction Dubas decides to go in.

“We probably don’t have a whole lot of bullets in the chamber here. We’re going to have to pick and choose as we set our sights,” he said on Sunday.

Sandin and Liljegren both figure to be big parts of the Leafs’ future but if one or both of them are able to show they’re capable of more right now, Dubas may not have to fire every one of those bullets he has in his chamber in pursuit of a top-four defenceman before the trade deadline.

Only time will tell, and Dubas intends to use all of the time at his disposal.