It’s a surprise and somewhat predictable. David Ellefson rejoins Dave Mustaine and Megadeth per the announcement on Monday February 8th, 2010. Megadeth is set to embark on “Rust In Peace 20th Anniversary Tour” starting March 2010 and at this point in time are busy rehearsing every single song from the seminal record.
The return of Ellefson into Megadeth ranks means a departure for James LoMenzo who recorded “United Abominations” and “Endgame” in 2007 and 2009 respectively. So far there has been no explanation what really happened within Megadeth with regards to LoMenzo.
Source: Megadeth.com