Washington Capitals rookie defenseman Jonas Siegenthaler (34) is expected to move into a fulltime NHL role next season. (Nick Wass)

The visiting locker room at PNC Arena in Raleigh, N.C., only has so many stalls, so before the Washington Capitals’ first game there in their first-round playoff matchup against the Carolina Hurricanes last month, rookie Jonas Siegenthaler was stationed in an auxiliary area. He was up with the big club for the postseason, a reward for a successful 25-game stint earlier in the year, but he hadn’t yet cracked the lineup for his Stanley Cup playoff debut.

That came days later, along with a new stall before Game 4 in the series. By the end of the series, he was playing on a top pairing with John Carlson, and while the Capitals ultimately fell to the Hurricanes in double overtime of Game 7, Siegenthaler’s play was a silver lining, especially as it pertains to the future of the blue line.

Washington has long touted defense as the jewel of its prospect pipeline, and with turnover to the Capitals’ corps expected this summer, that depth finally might be tested.

“Next season’s going to be huge," Siegenthaler said last month. "I’ll do my best in the summer to keep myself in even better shape. My goal is to be here a long time and for rest of my career, and yeah, just gotta work for it.”

The four teams that reached the conference finals all have mobile, aggressive blue liners who contribute to the offensive attack, a direction the Capitals have steadily moved toward. Washington’s defense suffered with slick-skating Michal Kempny out for the postseason after he tore his left hamstring, but he’s expected to recover by the start of training camp in September. He presumably will slot back into his usual spot beside Carlson, reuniting the team’s top duo. The second and third pairings, however, are expected to see some turnover a year after the Capitals returned the entire top six, which didn’t leave much opportunity for the organization’s prospects.

Veteran Brooks Orpik, 38, is considering retirement, and even if he does play next season, it probably won’t be with the Capitals, who are expected to run into salary-cap constraints. That cap crunch could force the trade of defenseman Matt Niskanen, who’s under contract for two more seasons at a $5.75 million hit. He struggled to start the season, then rebounded well, but with Washington’s midseason trade for Nick Jensen, Niskanen appears to be expendable. The Capitals quickly extended Jensen to a four-year, $10 million deal with a team-friendly $2.5 million cap hit, and like Niskanen, he’s a right-handed shot. Jensen is also four years younger and a better skater. He played in a mostly third-pair role with Washington, but he was averaging roughly 20 minutes per game with Detroit earlier in the season.

Christian Djoos’s second year with the Capitals was derailed by a two-month absence after compartment syndrome forced left thigh surgery, but as a restricted free agent this summer, he’s expected to be re-signed and perhaps play with Siegenthaler on the team’s third pairing. Orpik has been a constant there for the past three years, but with his likely departure, that duo is expected to get younger and more mobile while sacrificing some of the physicality Orpik provided.

“He’s been great for us over the five years," General Manager Brian MacLellan said of Orpik. “He’s done everything and more that we thought we’d get out of him. So, it’s been a good relationship. We’ll see how he does here with his injuries and his attitude and whether he wants to continue playing and whether we have room. Would we rather go with one of our younger guys instead of him? We’ll cross that bridge when he makes his decision.”

The Capitals’ past two first-round picks have been defensemen — Lucas Johansen in 2016 and Alex Alexeyev in 2018 — and since 2015, 12 of the team’s 22 draft selections have been used on blue liners. Johansen and Alexeyev both had injury-plagued seasons, with the latter injuring his knee in March. Johansen played in just 45 games in the American Hockey League this season, registering three goals and 11 assists; he scored six goals with 21 assists in 74 games last year. Washington was also high on right-handed shots Connor Hobbs, Colby Williams and Tyler Lewington, who played in two NHL games this season. Williams is a restricted free agent.

Siegenthaler has an edge on the field with his experience from this season, but there could be more than just one opening. The Capitals’ blue line hasn’t seen much turnover over the past few seasons, so this upcoming year potentially presents a rare opportunity.

“There’s always a bit of pressure, but at the end, you just got to play the game and just got to enjoy the moment," Siegenthaler said. "Not everyone is able to play in the Stanley Cup playoffs, and I think it was a huge experience, too, that takes you one more step further in your career. You’ve just got to learn from it.”