Defensive partners who eat together, warm up together, and work out together, stay together.

That’s the theory offseason acquisition Ryan Ellis and Ivan Provorov are working to prove throughout training camp as they learn each other’s tendencies, both on and off the ice. Their shared daily routine starts 2½ hours before practice when they arrive at the rink. From there, they get in breakfast, meetings, and warmups side-by-side.

On Tuesday, their schedule culminates in the Flyers’ first preseason game against the New York Islanders.

“[We’re] just kind of doing things together and getting to know each other off the ice,” Provorov said before the game. “And then on the ice getting used to each other during those practices and last little scrimmage here. Just very excited to get going and see what we can do together as a pairing during real games.”

Ellis, a right-handed defenseman who the Flyers acquired via trade with Nashville this summer, has 10 seasons, eight playoff appearances and 562 regular-season games to his name. The 30-year-old, offensive-minded defenseman boasts career totals of 75 goals and 270 points.

Twenty of those goals came on the power play, where Ellis will resume his duties with the Flyers. According to coach Alain Vigneault, Ellis figures to be a member of both the Flyers’ power-play and penalty-kill units. In practice on Sunday, Ellis worked with the second power-play unit alongside Provorov, center Derick Brassard, and wingers Cam Atkinson and Joel Farabee.

“Great player, smart player, and I think he does everything well on the ice. I wouldn’t say there’s anything that stands out that he can’t do,” Provorov said. “And then, you know, his work ethic off the ice is awesome, too. So we match up really well on and off the ice.”

In Ellis, Provorov looks to find a consistent partner who can bring out the best in him. Provorov worked through a carousel of partners last season — he played 34 games with Justin Braun, 14 with Shayne Gostisbehere, four with Travis Sanheim, and four with Phil Myers. He was in a different pairing every couple of weeks for the first half of the 56-game schedule, then he matched up with Braun for 23 of the last 24 games. Without a consistent partner, Provorov struggled to get into a rhythm, finishing the season with seven goals and tying career-lows with 19 assists and 26 points (albeit over a 56-game schedule).

While their newly established partnership has jelled well in training camp practices and off the ice, Provorov and Ellis look to establish that chemistry in-game for the first time against the Islanders. Then, they’ll aim to carry over a strong preseason into the regular season.

“You have to get along with who you’re playing with,” Provorov said. “Obviously, here we have — there’s not a guy that you don’t get along with. Everyone’s a great person and wants to win. So I think anyone you play with, you should be fine. But I think overall with Ryan, we match up pretty well.”

Breaking down the lineup vs. the Islanders

If the NHL preseason is a chemistry experiment in determining how each line, defensive pairing, and special-teams unit functions in a game-like scenario, then Vigneault is the mad scientist.

In the Flyers’ first preseason game against the Islanders at the Wells Fargo Center, Vigneault will meticulously evaluate how well each of the 22 players performs alongside their teammates before making tweaks going forward. Vigneault previously said he wouldn’t make drastic changes to the lines and pairings for the first week of training camp before they had an opportunity to play a preseason game.

“These guys have been paying attention to detail,” Vigneault said before the game. “I’m in the gym quite a bit seeing what’s going on there and there’s a focus and there’s an elevation of intensity at this time. I expected that. Now comes the exhibition. This is where decisions are made and players make those decisions for us by how they play.”

The Flyers’ potential No. 1 and No. 3 lines come the start of the season are slated to make their preseason debuts. The first line consists of center Sean Couturier with Claude Giroux and Travis Konecny on the wings. Oskar Lindblom and Atkinson centered by Brassard comprise the projected third line which will serve as the second line against the Islanders.

The remaining forwards on Tuesday all face an uphill battle to make the Flyers’ roster out of training camp but will have the opportunity to see how they measure up against NHL-caliber talent. On the third line against the Islanders, Connor Bunnaman will center Isaac Ratcliffe and Tyson Foerster. German Rubtsov will anchor the middle of the fourth line alongside Maksim Sushko and Max Willman.

On defense, two of the three veterans added in the offseason will put on a Flyers sweater for the first time. Ellis, who is paired with Provorov, and Keith Yandle, who will skate alongside Braun, have the chance to test the strength of their new pairings against the Islanders. Undrafted 21-year-old Egor Zamula and Nick Seeler round out the third defensive pair.

Carter Hart will get the start for the Flyers between the pipes and play the first two periods before Samuel Ersson takes over for the third. These preseason games will serve as an opportunity for Hart to build confidence heading into the season after finishing 2020-21 with a disappointing .877 save percentage.

“You just can tell the way he’s walking around, in the face and the eyes, he’s having — it seems to me anyway — he’s had a great focus, but he’s also having fun,” Vigneault said. “There’s no doubt that on the ice he wants to do well. He wants to perform. He’s done everything that has been asked of him so far, so I expect to do well on the ice tonight.”

On Thursday in Boston, Martin Jones and Felix Sandström will follow the same model — Jones will play the first two periods and Sandström will get the third. For the final four preseason games, Hart and Jones will likely split the time evenly.

Vigneault said that most of the players who will not participate on Tuesday are likely to compete on the road Thursday against the Bruins. Several prospects who are battling to make the opening-night roster — including Morgan Frost and Cam York — are among those slated to take the ice in Boston.

Islanders incoming

The Islanders are coming off of a 4-0 win against the New York Rangers on Sunday at Madison Square Garden in their first preseason game. According to The Athletic, defensemen Adam Pelech, Noah Dobson and forwards Anthony Beauvillier, Oliver Wahlstrom and Kyle Palmieri will make their preseason debuts.

Forwards Ross Johnston, Richard Pánik, Aatu Räty and defenseman Robin Salo will skate against the Flyers after playing against the Rangers. Johnston scored a goal and registered an assist against the Rangers. According to Newsday, goalie Cory Schneider will make his Islanders debut against the Flyers after Ilya Sorokin and Jakub Skarek combined for a 28-save shutout in the opener.

Injuries abound to start preseason

Eight Flyers are dealing with injuries and will, at the very least, miss the preseason opener. Those players are center Kevin Hayes (abdominal surgery on Sept. 21, out six-to-eight weeks), defenseman Samuel Morin (right knee surgery to have loose bodies removed on Sept. 10, out six-to-eight weeks), winger Wade Allison (right ankle sprain, out indefinitely), center Tanner Laczynski (hip), defenseman Linus Högberg (oblique, out seven-to-10 days), center Ryan Fitzgerald (lower body), winger Zayde Wisdom (shoulder surgery, out indefinitely), and defenseman Cooper Zech (upper body, out six-to-eight weeks).