At practice, Karlsson was paired with Marc-Edouard Vlasic, San Jose's top shut-down defenseman, for 5-on-5 drills.
"It's only the first day," Vlasic said. "Flew in late last night. He's jet-lagged, probably didn't get much sleep. He's had a lot going on the last week. Out of today, I didn't really get much out of it, but I've played against him for nine years now so I know that he's a very skilled player, can skate, good positioning. He does everything right, so it will be easy to practice with him."
Whether Karlsson, 28, a two-time Norris Trophy winner (2011-12, 2013-14), will open the season as Vlasic's partner has yet to be determined.
"Just want to get him in and used to the guys and get him comfortable," DeBoer said. "We have a lot of quality defensemen, and with him, we are going to try and maximize all of them. ... We're still in split groups. We haven't decided on any partners or pairs or who's playing with who. It's just practice right now."
When the Sharks finished practice with 3-on-3 work, Karlsson skated with defenseman Brent Burns, the 2016-17 Norris Trophy winner, and forward Joe Pavelski. On one play, Karlsson took a long stretch pass from Burns on a breakaway but was denied. On another, Karlsson sent a cross-crease pass to Burns, who scored on a tap-in.
"I think when you get to play with a guy who can skate like that, make plays, confident with the puck, it's great," Burns said.
San Jose defeated the Anaheim Ducks 4-1 Tuesday in its first preseason game and next plays Thursday at Anaheim. The Sharks' next preseason game is at home Saturday against the Vegas Golden Knights.
DeBoer said Karlsson, who arrived in San Jose late Wednesday, likely won't play in either of those two games, giving him more time to adjust to his new team and a new home.
"I landed, had a pizza, went to bed, woke up this morning, did what I had to do to get cleared to go on the ice, and went on the ice," Karlsson said. "I think that everybody in this organization, whether it's the players or the staff or the management, have been extremely welcoming in giving me everything that I needed to be as comfortable as I possibly can be, since it is a big move for me.
"I don't know anything else than Ottawa. I think today was more just about landing on my feet a little bit, getting to say hi to everybody, and take care of the things that I have to do. They gave me the space that I needed, and at the same time they gave me the comfort of letting me know if I needed anything. I think it was a perfect first day, and I'm excited to wake up tomorrow and go back to the rink."