Wide receiver Torrey Smith and quarterback Blaine Gabbert organized at least one informal, modestly attended practice at San Jose State last week before the 49ers reported for training camp Saturday.

Smith said about six other teammates, presumably wide receivers, attended.

“It wasn’t like we rallied everyone together,” Smith said. “It was like, ‘Who’s in town? OK, let’s go.’”

Smith said quarterback Colin Kaepernick did not attend. Kaepernick was in Vail, Colo., during the week and received medical clearance to participate in training camp after having had surgery on his thumb, shoulder and knee since late November.

“I guess he was traveling,” Smith said. “Taking care of his business.”

Smith and Jerome Simpson are the only 49ers wide receivers who have more than 36 career receptions. Anquan Boldin , 35, who led the team in receptions and receiving yards the past three seasons, signed with the Lions on Thursday.

Smith acknowledged that he needs to assume more of a leadership role with Boldin elsewhere.

“I think it’s definitely more pressure because before there was Anquan … as well as Jerome,” Smith said. “Now it’s just two of us. Obviously, with one person gone, there’s more responsibility for us to share. We’re going to make sure we’re doing things the right way.”

Help from the enemy: Defensive tackles DeForest Buckner and Arik Armstead spent part of their offseason training in Buckner’s home state of Hawaii with ... the enemy.

One of their training partners was Seahawks defensive end Michael Bennett , 30, a seven-year veteran who has 34.5 sacks since 2012.

“He definitely taught me and Arik a bunch,” Buckner said. “He took us under his wing for the couple days that we were working out with him. Even though he plays for the Seahawks, he was a really big help, helping us with our pass-rush game.”

Buckner, the No. 7 pick in this year’s draft, and Armstead, the No. 17 pick in 2015, are close friends who were teammates at Oregon.

In his first season, Armstead had 19 tackles and two sacks in an off-the-bench role.

Buckner’s goal for his rookie campaign? “To be honest,” he said, “win Rookie of the Year.”

Eric Branch is a San Francisco Chronicle staff writer.