Thursday morning it was about brass input.

Next Thursday, it’s about brass tacks.

Excluding Dennis Seidenberg, who is out another month recovering from back surgery, the preseason featured 14 defensemen vying for seven likely vacancies on the opening-night blueline. Take Bruins captain Zdeno Chara, Torey Krug and Adam McQuaid out as sure-fire Nos. 1-3 for now, and it leaves any combination for four slots from the remaining 11, led by Kevan Miller, Zach Trotman, Joe Morrow, and Colin Miller unless Sweeney makes a much needed deal for experience on the blueline with about $4 million in current cap space.

“For now” includes a question mark for Chara’s availability on opening night, compliments of an upper-body injury in the early going in his first preseason game on September 29. He is listed as “day-to-day.”

Into his 19th pro season and 10th as a Bruin, No. 33 played his lowest on-ice and on-the-stat-sheet total last season with 1195 career games under his belt. Nonetheless, he figures mightily in any Bruin bounce back season – on and off the ice. McQuaid has 283 career NHL games, Krug – 188, Kevan Miller – 88, Trotman and Morrow a combined 44; Colin Miller not a one.

“Zee can help (the younger players) with the knowledge of how we play,” GM Don Sweeney said at Thursday’s Media Day press conference, “and the level of expectations that it takes is where Zee’s really, really important for us.”

“Throughout the years, it has helped us become better,” echoed Claude Julien. “That’s where Zee is extremely good in that role. He’s been like that for many, many years, so obviously might be in a situation where he’s been more of that role — for example, this year. Sharing your experience is something that we’ve all done and something that comes easy to him.”

With so many young defensemen – and Krug elevated to No. 2 on the depth chart while beginning just his third NHL season – Chara is going to be really important on the ice, and really important on the bench.

“Now he’s more like a coach and a mentor for the younger guys,” Tuukka Rask said about Chara. “He’s looking forward to giving them leadership and advice.”

“The group coming in is willing to learn and ask questions,” Krug said. “It’s an easy conversation during the game. It flows nicely in the game about how to defend certain guys and the tendencies of certain players or teams.”

Morrow had first-hand experience learning from Chara last season in 15 games. He hopes to expand that number this season.

“He’s always in the right place at the right time and to play this long as good as he does, you have to be doing something right,” Morrow said on Thursday. “To be able to learn from that, any young guy on the back end will take from that. Yeah, there is a kind of coaching that goes on. You have your coach behind the bench clearly and he’ll give you all the advice he can, but you also get advice from someone on the ice as well.”

Is it a distraction during the game?

“You can process all that pretty quickly,” Morrow added, “and a minute between shifts gives time to think about what needs to be fixed or improved upon in the next shift.”

“We have young and good players on the back end,” Chara said about the D-corps. “You want to see the future. We all try to help each other and let each other know what a certain player likes or certain communications during a game; feedback about what’s working or not working. How you can read off each other better.”

“We need Zee to be the player he can be capable of,” Sweeney stressed. “You can’t put too much pressure on one player to do two things.”

Maybe Zee just being Zee reduces additional pressure.

Before being placed on waivers Thursday afternoon for the purpose of joining the Providence Bruins AHL roster, former Boston College defenseman Tommy Cross enjoyed Chara’s tutelage in the preseason.

“The way Zdeno works and prepares and executes is a perfect template for young guys,” Cross said.