David Backes was raring to go the week of the season opener. With the league a more welcoming place for faster and smaller players, the rugged forward worked on his skating in the offseason and streamlined his bulky physique for today’s NHL. But just a couple of days before the Bruins opener against Nashville, he was felled by diverticulitis, a digestive ailment that had him in the hospital for three days, doubled over in pain. Just when he’ll be able to make his season debut is not yet certain, but he participated in his first full practice yesterday since getting sick. Tomorrow night’s game against the Vancouver Canucks has not yet been ruled out. “I think we took a nice step today, being able to skate with the guys,” Backes said. “I was like a kid in a candy store before practice. You get the carrot of Game 1 taken away, and you finally get back with the guys after they’ve been away for a week. Knowing what the results have been, you want to inject a little energy out there, knowing we’ve got 77 games left to establish ourselves and finding our game and play the right way. “For me personally, I felt good out there. It was nice to be back on the ice. I was smiling most of the day knowing I’ll be playing ice hockey in the future.” The ailment came on in a hurry.