Weight, 39, has a torn rotator cuff and labrum in his left shoulder, injuries sustained in November. He has played through the pain, but said Saturday before the Islanders' morning skate in advance of their game against New Jersey that he will undergo surgery Thursday.
Weight had only one goal and 16 assists in 36 games this season. New York began Saturday in 14th place in the Eastern Conference, 11 points off the playoff pace with only 15 games remaining.
"It was probably inevitable and I don't know if I would've made it through the year even if we were in eighth or ninth," Weight said. "But I don't regret trying it."
Weight, a second-round pick of the New York Rangers in 1990, has 276 goals and 1,024 points in 1,220 NHL games. He was in the lineup Thursday when the Islanders lost 2-1 in a shootout to the St. Louis Blues, one of Weight's former teams.
He plans to work as hard as he can to resume his career next season. But the complexity of the surgery might make that impossible.
"I'm going to approach it with the aspirations of still playing hockey," Weight said. "I've still got the fire in my stomach when I hit the ice. My legs still feel strong, I feel strong on the puck. The rest will be written in the summer. I'll approach it to come back with 100 percent aggression.
"I'm going to attack this like I'm 25 and have to get ready for camp. But if Thursday was my last game, I have no regrets."
Weight is in his second season with the Islanders, but first as captain. Injuries -- including a bout with swine flu in October -- have limited him to 89 games since he came to Long Island as a free agent in 2008.
"It's not the type of hockey I wanted to play," Weight said. "I couldn't finish a check, I couldn't take a check, I couldn't handle the puck, I couldn't shoot the puck with velocity I was used to. I was spending 80 percent of my shift positioning myself so I didn't blow my shoulder out.
"I felt like if I could come back and rehab as hard as I could and contribute to a team that might make the playoffs, I would like to play in the playoffs."