Everything seemed fine after a 4-2 win against his old team, the New York Rangers Thursday night. He was smiling and laughing and enjoying the victory.

Long after his exile from Manhattan and Nashville, defenseman Michael Del Zotto has become the Flyers’ No. 1 defenseman.

That is, he will be after his latest string of bad luck.

The 26-year-old blueliner, whom the Flyers plan to rely on heavily, will miss four to five weeks with what the team calls a “lower-body injury.”

He was eager to start the regular season healthy after having to depart from the lineup in February when he tore tendons off his wrist.

“He was playing pretty good hockey,” coach Dave Hakstol said the other day. “The injury nagged him the last…at least several weeks while he was in the lineup.”

Del Zotto tried to play through it until he felt like he was a liability on the ice. He’d been given more responsibilities on the ice and played up to the challenge, being a key cog at even strength and on both special teams. When he went to get checked out, tests revealed it was worse than initially thought.

The Flyers are hoping that isn’t the case here, because they need him badly. Thursday the team announced that defenseman Brandon Manning would miss at least a week with an “upper-body injury” believed to be a sprained shoulder. Between the injuries to those two veterans, a roster spot if virtually assured for 2015 first-round pick Ivan Provorov.

General manager Ron Hextall will have a couple problems, though. He said Thursday, when he also announced that Scott Laughton will miss about a month, that he doesn’t want to put a player on long-term injured reserve to start a season. There are penalties associated with doing that right off the bat, but with Del Zotto’s $3.875 million salary-cap hit he may have no choice.