After Thursday's practice, head coach Travis Green says there was no update on Zub's lower-body injury.

The Ottawa Senators made a philosophical change to address their blue line this offseason. By electing not to qualify restricted free agent Erik Brannstrom and trading Jakob Chychrun to the Washington Capitals, the organization demonstrated the prioritization of two things: natural handedness to balance defensive pairings and size to bring more physicality to the lineup.

Adding Nick Jensen and having Tyler Kleven become an NHL regular were elements within the organization's control. Unfortunately, the Senators have little power regarding poor luck and injury prevention.

After participating in practices last week, Artem Zub has been conspicuously absent over the past two days. In his media availability yesterday, head coach Travis Green indicated that the right-shot defenceman was dealing with a lower-body injury and that the team would likely have more information available later in the day.

The hours passed without news, and after today's practice, there was no further update on Zub's health.

I will not speculate on his injury or how long the Russian will be out of the lineup, but his injury is mildly concerning for several reasons.

First and foremost, Zub is arguably the best defensive defenceman on the team. Advanced analytics certainly portray him as such. According to Evolving-Hockey's 'total defence' metric (DEF) combines a player's defensive contributions at even strength and on the penalty kill into one encompassing value, Zub accrued the most defensive value on the Senators last season. His 5.8 DEF value placed him 22nd amongst all NHL defencemen.

If Zub is forced to miss any time, it puts the team in an unenviable position. Granted, the organization has dealt with this situation before because his injuries have become a recurring problem. Over the last two campaigns, he has missed a half-season's worth of games. The organization is not renowned for its quality of defensive depth.

Adding Nick Jensen was a move designed to bolster the defensive zone play and balance the handedness of the top four. Behind him, Jacob Bernard-Docker and Travis Hamonic were expected to fill depth roles. Bernard-Docker appeared in 72 games last season, but provided just below league-average value in that spot. Hamonic is coming off a surgical procedure on his knee, which may have limited his effectiveness, but over the past several years, he has played at a sub-replacement level.

If Zub spends time on the shelf, it will force one of Hamonic or Bernard-Docker into the top four, where there is a greater chance of having their limitations exposed.

The Senators have four preseason games left before their regular season kicks off on October 10th against the Panthers, so Zub has time to heal. Getting in-game reps before the hockey means something would serve his conditioning and play, but Zub represents such a significant upgrade on the alternatives that it may not ultimately matter.

Should Zub's injury linger into the regular season, the waiver wire will be an intriguing place for the Senators to look to add. Competitors will inevitably trim their numbers as camps wind down around the league, which may lead to good players becoming available as teams try to sneak players through waivers.

Given the aforementioned quality of depth issues, this may be an avenue the team was already looking to explore because of the pressures of getting off to a good start.

The concerns about starting well while playing for a new coach are genuine. Poor starts have insurmountably sunk this organization's chances over the past several years, so fans are desperate for a change.