Question: What instrument was played by the man who was part of the New Grass Revival, along with Bela Fleck, John Cowan and Pat Flynn?

Context articles: New Grass Revival
New Grass Revival (1972 album)
Sam Bush
John Cowan
Do What You Gotta Do
Live (New Grass Revival album)
Deviation (Béla Fleck album)
Grass Roots: The Best of the New Grass Revival
Natural Bridge (album)
Mark Melloan

New Grass Revival was an American progressive bluegrass band founded in 1971, and composed of Sam Bush, Courtney Johnson, Ebo Walker, Curtis Burch, Butch Robins, John Cowan, Béla Fleck and Pat Flynn.
 They were active between 1971 and 1989, releasing more than twenty albums as well as six singles.
 Their highest-charting single is "Callin' Baton Rouge", which peaked at No. 37 on the U.S. country charts in 1989 and was a Top 5 country hit for Garth Brooks five years later.
New Grass Revival is the most commonly used title of an album recorded and released in 1972 by the progressive bluegrass band New Grass Revival on the Starday label.
 This album was also released under the titles, The Arrival of the New Grass Revival and Today's Bluegrass.
Charles Samuel "Sam" Bush (born April 13, 1952) is an American bluegrass mandolin player considered an originator of the Newgrass style.
John Cowan (born August 24, 1953 in Minerva, Ohio) is an American soul music and progressive bluegrass vocalist and bass guitar player.
 He was the lead vocalist and bass player for the New Grass Revival.
 Cowan became the band's bassist in 1972 after the departure of original bassist Ebo Walker and was noted as being the only member of New Grass Revival not to come from a bluegrass background.
"Do What You Gotta Do" is a song written by guitarist Pat Flynn and recorded by the New Grass Revival for their 1989 Capitol album "Friday Night in America".
 The song was also recorded by American country music artist Garth Brooks.
 It was released in January 2000 as fifth and final single from the 1997 album, "Sevens".
 The song reached number 13 on the U.S. "Billboard" Hot Country Singles & Tracks (now Hot Country Songs) charts and peaked at number 18 on the Canadian "RPM" Country Tracks chart.
Live is a live album by New Grass Revival, recorded June 3, 1983 in Toulouse, France, and released in 1984.
 It was the first New Grass Revival album to include Bela Fleck and Pat Flynn.
Deviation is an album by American banjoist Béla Fleck, released in 1984.
 It was recorded with the second classic line-up of the New Grass Revival, consisting of Béla Fleck, Sam Bush, John Cowan and Pat Flynn.
Grass Roots: The Best of the New Grass Revival is a compilation album by the progressive bluegrass band New Grass Revival, released in 2005.
Natural Bridge is an album by American banjoist Béla Fleck, released in 1982.
 Bela Fleck was a young bluegrass player whose work with such bands as Spectrum and the New Grass Revival pushed the envelope of bluegrass tradition and contributed to the development of the New Acoustic movement spearheaded by mandolinist David Grisman, guitarist Tony Rice, and others.
 Influenced by Bill Keith and Tony Trischka, he moved the banjo sound much further than anyone could imagine.
The 2002 album, "The Shadowlands," featured New Grass Revival founder Curtis Burch and three songs with banjoist Bela Fleck.
 The album was reviewed as "one of the best Americana bluesy collections", and Melloan was labeled "one of Kentucky's finest folk singer songwriters."
 Erika Brady, host of National Public Radio's Barren River Breakdown, described him as "an artist with extreme potential... His voice as a writer is very distinctive, and he's a good performer."