Seamus Casey Deep Dive: The Devils Prospect Facing a Make-or-Break Year
Seamus Casey can do things with the puck that most defensemen in the New Jersey Devils system cannot. That has always been true. The problem is he has not been on the ice enough to prove the rest of it.
That is why he ranks No. 5 in our 2026 Devils Prospect Rankings. The criteria still favor skating, puck skills, hockey sense, compete, and defensive detail, then production, trajectory, and NHL projection.
Casey’s offensive tools would put him higher if health and defensive consistency had kept pace. They have not. This season is the one that has to change that.
Background
Casey was born January 8, 2004 in Miami and drafted 46th overall in 2022. He is 5-foot-10, 181 pounds, and shoots right. He went the U.S. National Team Development Program route, then two years at Michigan. The sophomore season in Ann Arbor was the one that made people lean in. Seven goals and 38 assists in 40 games, First-Team All-American, Big Ten First All-Star. He signed with New Jersey in May 2024 and jumped straight into the pro game.
The NHL debut came fast. Injuries ahead of him on the Devils’ depth chart opened a door at the 2024 Global Series in Prague. He scored in his second game. A week later he had a multi-point night. Fourteen games that season produced 8 points. The sample was small and the shooting percentage was inflated, but the skill was not imaginary. He could run a power play and make the first pass under pressure.
Last year was supposed to be the follow-through. It was not. A lower-body injury kept him out of the start. He played two NHL games in late October — 18 minutes a night, no points, minus-3 — and was sent back to Utica. In the AHL he put up 19 points in 29 games, almost all assists, and earned another All-Star nod he could not attend. His last game was January 25. The rest of the year disappeared.
Two professional seasons. Fifty-nine AHL games. Sixteen NHL games. Too many gaps in between.
The tools that still rank
Let’s start with the hands. Casey is comfortable on both sides of the stick. He can take a pass in his feet, slip a check, and hit a moving target without needing extra space. The skating matches it. He is quick through the first three strides and can change direction without sitting down in his edges. That is how a 5-foot-10 defenseman survives at the next level. He arrives first and leaves with the puck.
The hockey sense is real on the offensive side. He sees the ice, walks the line, and does not panic when the first option disappears. In fact, he has the arsenal of a power play quarterback. In Utica last year the assist total told that story. One goal, 18 helpers. He was moving the puck more than he was finishing.
The other side of the ledger is why he is fifth and not third. Size is not a death sentence, but it is a tax. NHL forwards will finish checks on him. They already have. Defensive detail has to be sharper than the offensive highlights. Gap control, box-outs, net-front work — those are the nights that decide whether a small puck-mover stays in the lineup or goes back down. The two NHL games last October did not answer that question cleanly.
Compete is not the issue. He will engage. He even dropped the gloves in Utica. The issue is staying healthy long enough for the compete to matter over 70 games instead of 29.
The injury problem
This is not one bad break. It is a pattern.
He missed time as a rookie. He missed the start of last season. He missed the All-Star Game. He missed the second half. Devils head coach Sheldon Keefe said last year the organization wanted him in Utica for stability, not shuttle duty. That was the right idea. The body did not cooperate.
A 5-foot-10 defenseman cannot afford to lose half a year. The strength he needs, the defensive habits he needs, the trust he needs from an NHL staff — all of that is built in volume. Casey has not had volume. That is the entire argument for calling 2026-27 a make-or-break year.
NHL projection
If he stays healthy, Casey still projects as a puck-moving second-pair option at his ceiling. The offensive tools support a power-play role and a partner who can cover the net. Think Shayne Gostisbehere or Torey Krug.
The floor is an extra defenseman who can run the second unit in a pinch, otherwise he’s a top-pair AHLer. The ceiling requires the defensive game to catch up and the injuries to stop.
He is behind Anton Silayev because Silayev’s tools are rarer and the frame is built for NHL minutes. Yet, wouldn’t Silayev and Casey make for such an intriguing pair on Utica’s top unit, and perhaps some day in New Jersey?
Casey is behind Lenni Hämeenaho because Hämeenaho already handled a 33-game NHL sample without falling apart. Casey’s NHL flashes were louder, but they were also shorter.
The contract matters here. This is the last year of his entry-level deal with the Devils. He becomes a restricted free agent in 2027. New Jersey will want a clear answer before that paperwork comes due.
What this season has to look like
A healthy Devils training camp is non negotiable. Casey then needs real minutes if he does not make the team out of September.
No more 29-game seasons.
Casey is not fighting for a top-four job in September. He is fighting to stay in the conversation. Dougie Hamilton and Brett Pesce are the right-side regulars. Johnathan Kovacevic is already in the mix for third-pair minutes. Declan Chisholm can play both sides and has a real shot at a roster spot. That is a crowded group for a 5-foot-10 defenseman coming off a half-season.
The checklist is specific:
- Stay on the ice through camp and beyond.
- Defend the rush against bigger forwards instead of relying on the retrieve.
- Play 20 minutes in the AHL without the plus-minus falling apart if he is sent down.
- Show the same power-play poise he had as a rookie in New Jersey.
- Make Keefe trust him in a game that is not already decided.
He does not need to beat Hamilton and Pesce in October. He needs to make it impossible to ignore him by January. If camp is just another short look, Utica is waiting again — and this time the organization will want a full season, not another interrupted sample.
Verdict
Casey will go to camp and try to steal an NHL job. The more likely path is Utica again, this time for a full season, with call-ups only if he is healthy and producing.
He is still the most talented puck-moving defenseman in the system. Talent is not the question, however. Instead, it’s availability. If 2026-27 is another interrupted year, the ranking will slide. If it is the first healthy, complete season of his pro career, the conversation changes fast.
That could be the make-or-break. Not because of the skill, but the games played.