Now, it's recovery time, which should take about four to six weeks. He's expected to be ready for the start of training camp in September.
Kelly missed all of the postseason after his back seized up in Minnesota on April 8, in the Bruins' final week of the regular season.
A month and a half later, speaking with media during the Bruins' breakup day on May 16 - before he had the surgery - Kelly's back was still sore, and still had pain shooting down his leg as a result.
"But hopefully, I’ll get it fixed and it’ll be fine," Kelly had said.
Worse than that pain, was having to watch his team's final month of the season from the press box.
"I was just trying to do everything I could not to have surgery in order to play," said Kelly. "We were trying everything we could."
He never started skating before the end of the playoffs. When his teammates were on the ice, he was trying to recover. They missed his leadership, on and off the ice. He felt he could have contributed.
"Extremely frustrating. I thought the guys played really hard and did a great job - it’s difficult to watch, you’re still invested in the group, but it’s kind of out of your control, so it was difficult," said Kelly.
Before he suffered the injury, he and his linemates - Loui Eriksson and Carl Soderberg - had been hitting their stride.
A healthy Eriksson returned from the Olympics and played his best hockey of the year, while Soderberg switched to center and 'let his hair loose' as Kelly would say. It was Kelly's move to left wing that allowed the switch to happen. They had two strong, defensive-minded centermen as a one-two punch.
The Bruins were primed to have their strongest third line in the playoffs since 2011, and this trio could have proved even stronger than that year.
"I think another frustrating part was I felt that Carl, Loui and myself were actually forming real good chemistry and being able to play well and getting to know each other on the ice was a good thing," said Kelly.
Luck wasn't on their side, though. To start the year, it had been Eriksson's misfortune with concussions keeping them apart, and then Kelly's leg injury (broken right fibula) kept him out for 22 games in December and January, before his back injury kept them apart in the postseason.
"Obviously with Loui getting a couple injuries and then myself with some injuries, it was tough, but when we did play together, it was extremely fun."
Kelly had never missed sustained time with injuries before the 2012-13 season, when he spent a month out of the lineup recovering from a broken left tibia (shinbone). Now, he's been faced with back-to-back seasons of frustration.
"Yeah, obviously when you get injured in a year, it’s a frustrating year," said Kelly. "But those things happen. I think it makes you stronger as a person, as a player, and you just push forward."
Faced with another recovery in the offseason, there's no doubt that the Bruins' alternate captain will again be doing everything he can to be in peak condition for next season.
In 2014-15, Kelly will enter the third season of his current four-year deal (with a no-trade clause). He's enjoyed his time here; he would just like a little more luck on his side to be able to contribute night in and night out.
"Who wouldn’t want to be here?" said Kelly. "This is a great team. We had another great team with a great year and we accomplished a lot. Obviously it’s disappointing. You’re going to be disappointed regardless when you lose. I think the only time this group has been smiling at the end of the year is a few years back."
"So expectations are extremely high here, and rightfully so."
Lucic Has Successful Surgery on Left Wrist
Milan Lucic also underwent successful surgery, General Manager Peter Chairelli announced on Friday, May 23, to repair his left wrist.
During the team's breakup day media availability on May 16, Lucic was seen with a brace on that wrist. He had gotten it caught and jammed it in the first period of Game 7 against Montreal.
Besides that, he was able to stay healthy all season, and through the playoffs.
"Fortunately it was a healthy, healthy year," Lucic told media that day. "And the two games that I did miss were both because of the flu. I was able to keep myself healthy all year long, performing at the level that I wanted to."
"I felt like I was able skate well. I had one of my best skating years, as far as the season goes there. You always want to keep improving to get better. With this loss, I think it’s definitely something that’s going to motivate you in the summer."