To paraphrase the old Bill Parcells line, you don’t know anything about an athlete until he gets punched in the nose. There’s nothing like a little adversity to bring a players’ mettle, or lack thereof, to the forefront. Bruins coach Bruce Cassidy’s punch was figurative, not literal, but his sock to Jake DeBrusk’s schnozz by way of a healthy scratch has produced the desired effects. Since taking a seat on the Garden’s ninth floor Nov. 11 to watch a loss to Toronto, DeBrusk returned to the lineup for the B’s three-game California excursion and showed the jump that had been missing from his game before the scratch. The rookie was good in the first two games, compiling six shots on net and picking up an assist. And he was a star in the B’s 3-1 victory Saturday against the Sharks, making a spectacular move through two defenders to set up Peter Cehlarik’s first NHL goal, then outracing Brent Burns for his fourth goal. Healthy scratches don’t always produce these results, but it’s nice when one does — especially with a highly touted youngster like DeBrusk, the 14th overall pick in 2015. “He’s got pride and character,” said Cassidy after the B’s second straight win. “We’ve talked about these young kids coming in here and how (DeBrusk) grew in Providence (of the AHL) last year as a player. That was part of it with Jake. He wanted his opportunity. He didn’t get it last year. He’s gotten it this year.