Marleau has not played since the 2019 Eastern Conference First Round, when he had two assists for the Toronto Maple Leafs in a seven-game loss to the Boston Bruins.
"This is an opportunity to add a veteran into our group to give us some veteran depth that's versatile, understands how we play, and is very accepting of the role that (coach) Pete DeBoer may need on different nights," Wilson said.
Before signing with the Maple Leafs on July 2, 2017, Marleau played 19 seasons for the Sharks. He is San Jose's leader in games (1,493), goals (508) and points (1,082), and has played 788 consecutive games, including last season, when he had 37 points (16 goals, 21 assists) for Toronto.
"I think he can give us a boost," DeBoer said after San Jose lost 5-2 at the Nashville Predators on Tuesday, its fourth straight loss to start the season. "He's an experienced guy. He's not going to panic under pressure. He's going to make the right play. He's a big, strong guy. I think he fits with how we want to play.
"… He hasn't been through training camp or anything, so we'll see where his conditioning and stuff is at. But there's no doubt he can help us."
On June 27, the 40-year-old forward had the final season of the three-year, $18.75 million contract (average annual value $6.25 million) he signed with the Maple Leafs bought out by the Carolina Hurricanes, making him an unrestricted free agent. Carolina acquired Marleau in a trade from Toronto on June 22 with a conditional first-round NHL Draft pick and a seventh-round pick in the 2020 NHL Draft for a sixth-round pick in 2020.
"He should be playing somewhere," Sharks center Joe Thornton told The Athletic on Tuesday before it was known Marleau was returning. "I expect he'll be somewhere soon. He skates with us in the summer and he's still the best skater on the ice."
Marleau, selected by San Jose with the No. 2 pick in the 1997 NHL Draft, has 1,166 points (551 goals, 615 assists) in 1,657 NHL games and 127 points (72 goals, 55 assists) in 191 Stanley Cup Playoff games.
He is fifth in NHL history in games played (1,657), 28th in goals, tied with Rod Gilbert for 82nd in assists and 53rd in points.
NHL.com Independent Correspondent Robby Stanley contributed to this report