By Scott McLennan

Avoiding pat formulas and enlisting unexpected aides de camp are probably the only ways that Bob Weir and his fellow founding Grateful Dead mates can avoid turning into a stale nostalgia act.

Dead & Company at Gillette Stadium, Foxborough, MA on June 22.

(R to L) Dead & Company’s guitarists John Mayer and Bob Weir flank Bill Kreutzmann on stage at Gillette Stadium. Photo : Courtesy of David Silverman | Kraft Sports + Entertainment.

Deadheads of a certain age (see hand in air) may never get used to watching a guitarist wearing a Madonna t-shirt on stage as he conjures up the requisite jams that propel such Grateful Dead gems as “Eyes of the World,” “Bird Song” and “Dark Star.” But John Mayer’s fashion sense aside, Dead & Company constructed a beauty of a concert Saturday at Gillette Stadium in Foxborough.

It seemed both nutty and disingenuous when founding Grateful Dead member Bob Weir enlisted Mayer to join him, original Dead drummers Bill Kreutzmann and Mickey Hart, plus keyboard player Jeff Chimenti and bass player Oteil Burbridge to form Dead & Company in 2015 shortly after a series of Grateful Dead “farewell concerts” that included remaining founding member Phil Lesh on bass and Phish guitarist Trey Anastasio.

Dead & Company has definitely evolved in its search for a place within the post-Jerry Garcia Grateful Dead universe. When virtuoso guitarist and de facto Grateful Dead leader Garcia died  in 1995, that forced Weir, Lesh, Hart and Kreutzmann into finding new ways to keep alive both a unique rock ‘n’ roll songbook and a popular, ritualistic music scene.

With Mayer, Weir found the “anti-Jerry” – a player who was shaped by Berklee, not Berkeley; a player with a pop pedigree, rather than one with a passing grade from the Acid Test; a player who has better social media chops than shamanistic mystique.

But make no mistake: Mayer can craft a blazing guitar line around just about anything tossed his way. And that may have contributed to the flaws in Dead & Company’s earlier outings; Mayer tended to overstuff his solos, worrying more about quantity over quality. That may in part explain why Weir and the drummers took to slowing the tempos on almost everything the band played.

This summer, Dead & Company seems to have found the right balance, evidenced by the stellar show in Foxborough and hearing the recordings of recent concerts now streaming online. Mayer is playing with more patience, and the ensemble jams benefit from the kind of slow burn intensity that comes from musicians who listen to and trust each other. Inspired by the better feel among the players, the tempos perked right up.

Dead & Company opened its Gillette Stadium outing with a richly played “Eyes of the World,” a song the Grateful Dead would usually save for the longer, more expansive second set of a concert. But on this tour Dead & Company is mixing up old routines to good effect; the band didn’t even play “One More Saturday Night” at this Saturday night affair.

Avoiding pat formulas and enlisting unexpected aides de camp are probably the only ways that Weir and his fellow founding Grateful Dead mates can avoid turning into a stale nostalgia act while sticking to a repertoire of songs mostly dating back to the 1960s and ’70s.

So after the long, exploratory “Eyes,” Dead & Company maneuvered into the rollicking “Deal,” a song Garcia would usually bust out to end a first set.

Weir’s majestic ballad “Black-Throated Wind” followed, and the group sustained the tune’s ethereal vibe without backsliding into a dirge.  Weir was in great form all night, taking the lead on signature Garcia songs “Loser” and “Bird Song”

The other promising signs out of 2019 Dead & Company are, believe it or not, glitches. When an improvisational band screws up — and the Grateful Dead would screw up a lot — it’s usually because the band is under rehearsed or playing in the moment.

On Saturday, the errors seemed more indicative of the latter. First, Mayer teed up the song “Big Boss Man” with a few muscular bluesy chords, only to have everyone else playing the song “Easy Wind”; it worked out and everyone was on the same page within a few bars of “Easy Wind.”

And to close the first set, Dead & Company unpacked “Box of Rain,” a Phil Lesh staple that this band hasn’t played since 2016. Mayer became hopelessly lost in the lyrics, prompting Weir to halt the song and proclaim “Take two.” From there it was smooth sailing and a more humanizing than humiliating situation for the band.

Dead & Company’s second set was a nearly two-hour psychedelic sprawl that showcased the individual talents within the band as well as the deft ensemble playing this group is capable of. The set began with the sequence of “Help on the Way,” “Slipknot” and “Franklin’s Tower,” angular songs from the Dead’s mid-’70s experimental period. The crowd-pleasing triplet has been played at Dead & Company’s previous outings at Fenway Park, but this year the band swung way out on the improvisational sections and seamlessly found its way back to each song’s core, ratcheting up the energy to an explosive point by the time it arrived at the climatic lines in “Franklin’s Tower”: “If you get confused, just listen to the music play.”

All this bode well for the remainder of the concert, with a smoldering “He’s Gone” nicely loping into an epic reading of “Dark Star,” the Holy Grail of mind-bending anthems. The band warped and reshaped the tune with a bit of Latin jazz bounce carried over from an improvised section into the song’s closing verse.

A segment of percussion jams and free form playing coalesced around the Garcia ballad “Stella Blue,” nicely handled by Weir. Dead & Company closed the set with an extended take on Buddy Holly’s “Not Fade Away” that sandwiched the traditional folk song “Going Down the Road Feeling Bad” – two covers that have been part of the Grateful Dead repertoire since its earliest days.

Dead & Company encored with “The Weight,” another cover, but one that was adopted much later by the Grateful Dead and reconfigured once again by this lineup. That seems to be at the heart of Dead & Company — recasting, refurbishing, and constantly rethinking the Grateful Dead legacy.

Scott McLennan covered music for the Worcester Telegram & Gazette from 1993 to 2008. He then contributed music reviews and features to The Boston Globe, The Providence Journal, The Portland Press Herald and WGBH, as well as to the Arts Fuse. He also operated the NE Metal blog to provide in-depth coverage of the region’s heavy metal scene.