Jagger, 78, who had heart surgery in 2019, was also ambivalent when asked if this could be the Stones last tour
The Rolling Stones get back on the road this weekend without drummer Charlie Watts, whom frontman Mick Jagger called the rock that held the band together.
In interviews with Rolling Stone music magazine writer David Fricke, Jagger, Keith Richards and Ron Wood talked for the first time about their memories of Watts, who died in London a month ago at age 80.
They declined to speculate on whether this would be the band's last tour.
The "No Filter" tour, whose US leg kicks off on Sunday in St. Louis, Missouri, will be the first without Watts since 1963.
"He held the band together for so long, musically, because he was the rock the rest of it was built around," Jagger said in the interview released on Thursday.
"The thing he brought was this beautiful sense of swing and swerve that most bands wish they could have. We had some really nice conversations in the last couple of years about how all this happened with the band," Jagger added.
"It's a huge loss to us all. It's very, very hard. But we had wonderful times, and Charlie made some wonderful music."
Drummer Steve Jordan will play with the Stones on the tour. He had been announced in August as a temporary replacement for Watts, who needed time to recuperate after unspecified surgery.
Richards, 77, said going ahead had been a hard decision.
"We hit a very difficult point, to take this thing out. But we're gonna do it," he said.
"Charlie was prepared for us to go ahead. We were expecting him to pick it up somewhere. Steve was, thankfully, going to be the pickup. But things ain't turned out that way."
Getting back on stage without Watts is "a very surreal feeling," Wood said, but he noted that rehearsals with Jordan had gone well.
As for the band's future on the road after the 13-date U.S. tour ending in November, Richards agreed that the gigs would help the members find out "what's right and possible."
Jagger, 78, who had heart surgery in 2019, was also ambivalent when asked if this could be the Stones last tour.
"I've been asked that question since I was 31," he said.
"I don't know. I mean, anything could happen. You know, if things are good next year and everyone's feeling good about touring, I'm sure we'll do shows. I'm just trying to concentrate on this tour now."