BOSTON — The regular season began two weeks ago, but TD Garden might have an opening-nght atmosphere on Thursday — at least as far as some aspects of the Bruins’ lineup are concerned.

Veteran forwards Patrice Bergeron and David Backes could finally kick off their 2017-18 season when the B’s begin a four-game homestand against the Canucks (7 p.m., NESN, WBZ-FM 98.5). Injuries have kept both out of the Bruins’ first five games, which is one of the reasons they’re only 2-3-0 despite playing four games against teams that missed the playoffs last season.

Bergeron (lower body) and Backes (diverticulitis), who both sailed through training camp, practiced for the second straight day on Tuesday. Bergeron, although dressed in a red no-contact jersey, has initiated contact on several occasions; Backes has practiced with no restrictions.

“In the past, we’ve basically ruled [Bergeron] out ahead of time,” coach Bruce Cassidy said after Wednesday’s practice. “We’re not ruling him out for [Thursday], but I’m not saying he’s in. Backes looks closer to being ready to play.”

While the presence of Bergeron and Backes will allow Cassidy to restore some lines and power-play groups he planned to use at the start of the season (Bergeron, Brad Marchand and rookie winger Anders Bjork being one of them), the coach might still have to change on the fly: A goalmouth collision with Bjork knocked No. 1 goalie Tuukka Rask out of Wednesday’s practice (Bjork escaped with a bloody chin), and center Ryan Spooner, who left Sunday’s 3-1 road loss to the expansion Golden Knights, has been diagnosed with a groin adductor tear that’s expected to sideline him for 4-6 weeks.

Cassidy said decisions regarding Thursday’s lineup “all start at the top,” meaning who plays and who doesn’t depends on whether Bergeron and Backes are available.

Most of a pre-existing line might be unveiled, either way. The Bruins recalled wingers Kenny Agostino and Peter Cehlarik, who had been centered by rookie pro Jakob Forsbacka-Karlsson, from AHL Providence on Wednesday, and had veteran Riley Nash — Bergeron’s replacement to date — skate between them.

Agostino, the AHL leader in points (83) and assists (59) last season, was 2-5-7 in the P-Bruins’ first three games, and was named AHL player of the week. Cehlarik, a second-year pro who played 11 NHL games last season (two assists), was 2-3—5 through three games at Providence.

“If [Agostino and Cehlarik] are in the lineup, it’s definitely a possibility,” Cassidy said of the prospect of keeping them together. “We do like their chemistry, and ideally, if they could play together, it probably helps them as much as it helps us.”

Neither Agostino (2-3—5 in 17 career NHL games), whom the Bruins signed as a free agent over the summer, nor Cehlarik had the best opportunity to win a job during training camp: Agostino missed about a week with an injury (although he did go 1-2—3 in three preseason games), and Cehlarik – to his dismay -- continued to rehab from offseason shoulder surgery.

“I was maybe too positive coming into camp,” said the 22-year-old Slovak, a third-round draft pick (No. 90 overall) in 2013, who wasn’t allowed contact for virtually all of camp. “I felt like I was in good shape, but they told me to be patient with it. I had to go through some process to get the shoulder ready.”

Agostino, 25, had to sweat out the waiver process when the B’s decided to assign him to Providence.

“You never know with those things,” said Agostino, who assumed Spooner’s half-wall position during power-play drills on Wednesday. “I cleared, and that’s all that matters. [Assignment to the AHL] is an opportunity to get better, and I think I did that.”

AROUND THE BOARDS: Defenseman Adam McQuaid, forced out of Sunday’s game after taking a shot off the right leg, practiced Wednesday after two days off the ice. He expects to play on Thursday … Cassidy switched all three defense pairs in practice, teaming Zdeno Chara with rookie Charlie McAvoy, McQuaid with Kevan Miller and Torey Krug with Chara’s usual partner, Brandon Carlo … Veterans Matt Beleskey and Frank Vatrano practiced on what amounted to a fifth line, centered by tryout candidate Ryan White.