Testament parted ways with drummer Gene Hoglan on January 21 due to conflicting schedules. Hoglan originally drummed for Testament between 1996 and 1997, and then again from 2012 to present day. The band also made it know that they've got "yet another top notch addition to Testament."
So while we're waiting for that announcement, here are a few drummers that could certainly join the band without a problem!
Bostaph drummed for Testament between 1992 and 1993, 2004 and 2005, 2006, and then 2007 to 2011. So Bostaph has seen a pretty solid amount of Testament over the years and was the last drummer to hold the throne prior to now-ex drummer Gene Hoglan. Plus I'm sure playing in Slayer for their last six years certainly helped sharpen his proverbial blades.
Sure, Lombardo only drummed in Testament between 1998 and 1999, but the dude has basically not stopped playing drums for the past few decades. Much like Bostaph, Lombardo is out there killing it on a regular basis. And if Lombardo could step in as Metallica's live drummer on an insanely short notice like he did at Download 2004, I'm sure he can learn Testament's material as well.
Hey look, another ex-Slayer guy! Dette drummed in Testament between 1994 and 1995, and then again in 1997 and 2000. Dette also filled in with Anthrax for a few years in the 2010s. So the guy's been in Testament, has joined and filled-in for Slayer, and has had to learn Charlie Benante's drum parts in Anthrax. I'm willing to be that Dette is more than capable.
Barker drummed for Testament as a full-time thing in 2007, but was their live fill-in between 2006 and 2007. Barker has also filled in for bands like Anaal Nathrakh, Exodus, Gorgoroth, and Benediction over the years, so I think it's safe to say that he's got a wide range of metal-related styles firmly under his belt.
Adler has been keeping himself busy with his new band Firstborne lately, but they're hardly a touring powerhouse. Adler did one hell of a job in Lamb Of God over his 20-year tenure in the band, and did an equally great job with Megadeth both live in the mid-2010s and on their 2016 album Dystopia. Plus he already contributed drums to an alternative version of Testament's 2014 track "A Day In The Death" found on the deluxe edition of Dark Roots Of Earth.
Axenrot recently parted ways with Opeth and is still the current drummer for Bloodbath, who aren't exactly known for their extensive touring schedule. Axenrot is an incredibly versatile drummer that had to cover everything from outright death metal to more complex progressive parts in Opeth, making him an interesting (but still solid) choice for Testament.
BONUS DRUMMER: Travis Barker
Why not? Everyone else is doing it.