SONNY ROLLINS, who bedazzles audiences with unaccompanied tenor saxophone solos and mystifies fans with his periodic sabbaticals, had the most pristine listeners shaking their heads in wonderment at the White House Jazz Festival in June.

"Sounds like Sonny wants to play seriously again," said jazz fan Morrison Hansborough, who rarely misses a nearby Rollins performance.

"Listen to Sonny up there playing that slutty blues," laughed writer Albert Murray, while Rollins (with percussionist Max Roach, pianist McCoy Tyner and bassist Ron Carter) swung "Sonnymoon for Two" as if he had returned, like a prodigal son, from the neon world of fusion music to the pastels and earthentones of unelectrified jazz.

And that's the way he's been sounding recently. In the last month, jazz fans all over the country, from Santa Barbara to Chicago, have been seeing the "new" Rollins in an unusual tour with Tyner, Carter and drumzner Al Foster. The reviews have been unanimous in their praise and audiences have been enthusiastic.

The group, called the Millestone [WORD ILLEGIBLE] (Rollins, Tyner and Carter record for Millestone), is to perform Friday night at the Kennedy Center. The 19-city tour ends two nights later in Philadelphia.

The tour, most people agree, is important because for the first time in more than a decade Rollins is being heard with musicians who are his peers, not the relatively inexperienced, rock-influenced performers he's surrounded himself with recently.

The cross-country tour is also significant for its presentation of a non-electric, non-fusion group in the nation's major concert halls, an uncommon and financially risky venture in this era of musical hype.

Carter told critic Leonard Feather: "There will be no synthesizers on the piano; people will see a drum kit for just one drummer, rather than a whole drum-shopload of equipment; they will observe no pedals around our feet, and they will not hear Sonny Rollins' horn short, what they see will be what they hear."

Rollins, 48, a standard bearer of the seaxophone tradition of Coleman Hawkins, Lester Young and Charlie Parker, concedes that his recent work has been heavily marked by rock styles - a trend followed by other jazzmen such as Herbie Hancock, Freddie Hubbard and Miles Davis.

"In my group, I've been going sort of in a more contemporary direction, using some electric instruments playing behind me, and also making use of a lot of the cross-rhythms which are happening in music today," he says.

He explained the direction of his music this way several months ago: "There's a certain energy that's important in music, especially the music I play. Now, to play standards and older songs you need a group of people to interest them. It requires a certain energy and familitarity.

"Many young musicians today are not familiar with the standards. But many guys of my own age don't have the energy to play these things in a fresh way. A high energy loved is very apprepriate to my playing."

Apparently, Rollins has been inexpired by Tyner, Crter and Foster, musicians who are slightly younger than the saxophonist. They're periormers who, is Rollins' words, can "relate to some of that music (standards) and at the same time make it not sound backneyed."

The energy element is pervasive in an album recorded in April, "Don't Stop the Carnival" (Milestone M-530000, in which Rollins finds himself with drummer Tony Williams, trumpstar Donald Byrd (both jazz artists who went fusion) and a pianist, a bassist and a guitarist, all of whom are young and rock-oriented.

The saxophonist's performances are stunning for their mixture of roaring melodic invention an rhythmic tension.

In "Silver City," for example, he creates burlesque effects by smearing notes, constructs cascades of sound by playing long flurries of notes bent into each other and humorously interpolates forgotten popular melodies.

In another recent album, "There Will Never Be Another You" (Impulse LA-$349), a more straight-ahead Rollins is on view. Recorded at a concert at the Museum of Modern Art, the record is a marvelous reminder of the saxophonist's melodic strengths and rhythmic thrusts even though the program is made up of standards.

What will be heard Friday night promises to be a variety of sounds and colors. "It's not just four guys playing together," says Rollins. "We do duos, trios and solos. And though we have a basic repertoire, we change the pieces we play from night to night. It's a challenge. We all look forward to performing together."