An Emphasis on ‘Exploring’ : Saxophonist Grover Washington Jr. has made diversity the cornerstone of his ever-changing musical style.

Musical diversity is a tough enough business, and now saxophonist Grover Washington Jr. has more than two decades of personal history to deal with whenever he walks on stage. The trick every night is mixing his upbeat rhythm and blues with his more delicate ballads, his crowd-pleasing fusion with critic-pleasing straight-ahead jazz.

“I have about 25 albums now,” said Washington, 49, calling from home in Philadelphia during a brief tour break. “That is part of the problem. We only have an hour and a half to play. We just try to play as much music as possible.”

That will be his mission Sunday night when he performs at the Universal Amphitheatre with his six-piece touring band. Along with his more recent material, the saxophonist is likely to play some excerpts and medleys from such top-selling albums as 1974’s “Mister Magic” and 1980’s “Winelight,” which sold more than 2 million copies.

If time permits, Washington said, he and a pianist will share a duet of a Duke Ellington tune, or some other immortal jazz standard. “That’s to let (audiences) know that music is music,” he said, explaining this occasional slide into a traditional mode. “And if it wasn’t for the musicians who came before us, we wouldn’t be here. We’re just caretakers of the music right now.”

While his greatest commercial successes have centered on his fusion and R & B work, Washington makes a point of spending time doing session work in a variety of genres. In recent weeks he’s recorded with veteran jazz pianist Mal Waldron, a bandleader for singer Billie Holiday near the end of her life, for an upcoming Japanese release.

In mid-December, Washington will join singer Kathleen Battle at Carnegie Hall in New York for a mixture of classical, jazz and spiritual works.

Some of that diversity has emerged in Washington’s own music. In the late-1980s, his classical piece “Suite in Three Colors” was performed in Los Angeles by the New American Orchestra. And on his latest album, 1992’s “Next Exit,” the saxophonist and his band created an aggressively modern reading of Paul Desmond’s “Take Five.”

“When you have a good piece of music that has been done the same way a thousand different times, it’s part of your musical responsibility to try to change the presentation of it,” Washington said, “as long as you don’t change the essence of the piece.”

By contrast, that same album ends with “Check Out Grover,” which combines a sly R & B groove with rap vocals by Man Slaughter and hip-hop beats by Doug E. Fresh. “It was meant as a fun piece, and to let folks know we aren’t finished exploring,” he said.

As a player and leader, “Washington continues to be the most skilled of the cross-over reed men,” wrote Times critic Bill Kohlhasse of an August performance in Orange County.

But much of Washington’s material is far from what some critics and jazz traditionalists would prefer to hear him play. While many praised his 1988 straight-ahead jazz recording “Then and Now,” which teamed him with such players as Herbie Hancock and Ron Carter, critics have often been uninterested in his fusion work.

So he finds himself pulled in a variety of musical directions at any one time: the early hits that made his career, his new work, and the timeless straight-ahead vein, among other styles.

“I will get to all those musical directions,” Washington said. “The only thing I want the critics to do is have a little bit of patience because I will get to all these things, and probably to a lot more things, too.”

Where and When Who: Grover Washington Jr. with Rachelle Ferrell. Location: Universal Amphitheater, 100 Universal City Plaza. Hours: 8:15 p.m. Sunday. Price: $22.50-$34.50 plus service charge. Call: (213) 480-3232.