Norris, who weighed 232 when the season began on April 6, said before Friday's 4-2 win over the D-backs that he's at his lowest weight since high school.
Norris has found a way to make sure his weight loss -- something not uncommon for catchers -- hasn't been greater than the 12 pounds.
"I don't normally stray away from the buffet table too often. I usually do a good job eating," he said.
Norris has played 561.1 innings behind the plate, which trails only Yadier Molina of the Cardinals (567).
But Norris, who is hitting .163 in June after a hot start when he hit .313 in April, said the weight loss hasn't affected his game, offensively or defensively.
"I feel good," he said. "I've been doing regular maintenance, getting stuff you need to get done in the training room, as far as arm, keep it fresh, cold tub after games, stretching, foam rolling," Norris said.
"There's no real trick. If something is getting dinged up, just get in there [training room] and get it knocked out. I've been blessed. Knock on wood. Things have been healing up whenever I get dinged up."
Norris has never started more than 93 games in one season in the big leagues, and that was last season with the A's. His start Friday was already his 61st of the season. Norris said during Spring Training that he wanted to catch in upwards of 120 games.
"I always expect that for me, to be in there every day," Norris said. "Defensively I feel like I've been solid. I feel on the field I have a presence this team needs and respects."
Norris has thrown out the most would-be basestealers in the game (24) and his framing skills have gotten a little better as well -- in terms of extra strikes received. Even with adding Austin Hedges, the Padres haven't given Norris many additional days off.
Hedges, who was recalled on May 3 from Triple-A El Paso, has started 11 games.
"Derek is our guy and he's going to catch very often," said Padres interim manager Pat Murphy. "You have to try to monitor it a little and give him a blow, like we did yesterday. He's done a great job this year. He's on a mission to lead this team from behind the plate."
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.