IT'S ANYBODY'S guess as to who will pop up on pianist McCoy Tyner's recordings these days. His latest releases, for example, feature guitarist John Scofield, tenor saxophonist George Adams and violinist Stephane Grappelli.

Scofield appears in cameo on the album "Things Ain't What They Used to Be," coolly illuminating the angular contours of Thelonious Monk's "I Mean You" and contributing silvery trumpet-like lines to Clifford Jordan's jazz perennial "Joy Spring." Likewise, Adams proves a worthy duet partner on a couple of tunes, particularly Tyner's own "Blues on a Corner," which finds the often explosive saxophonist weaving a sinuous melody around Tyner's quirky harmonies.

But what really distinguishes the album are the eight solo performances. A delightful offshoot of a record Tyner released last year, the virtuosic solo collection "Revelations," the album includes Tyner's grand and robust overture, "The Greeting"; a spiritual reading of John Coltrane's "Naima"; and a typically percussive and persuasive version of the Mercer Ellington title track.

As for Grappelli, the venerable swing master lends a hand on Tyner's "One on One" album, a surprisingly compatible series of duets. Tyner may defer to Grappelli's elegant lyricism at times, toning down his sharply percussive attack, but as he proves on the richly harmonized "How High the Moon" and "Mr. P.C.," he's not about to take a back seat. As a result, this collection of mostly well-worn standards, including "Satin Doll," "St. Louis Blues" and "I Got Rhythm," is always refreshing and sometimes inspired.

MCCOY TYNER -- "Things Ain't What They Used To Be" (Blue Note) and "One on One" (Fantasy). Appearing Friday at the Montpelier Cultural Arts Center, 12826 Laurel-Bowie Rd., Laurel. Call 301/953-1993.