Heavyweight champion Volkov (19-3), who was initially slated to lock horns with undefeated challenger Vitaly Minakov (12-0) in the headlining bout of Bellator 109, will now look to defend his belt in the co-main event of Bellator 108, underneath Rampage Jackson's promotional debut opposite Joey Beltran.
Likewise, Shlemenko's upcoming middleweight title defense against Doug Marshall (18-6) has been moved from the co-main event of Bellator 108 to the main event of Bellator 109.
Bellator officials announced the switch Tuesday.
Bellator 108 takes place November 15 at the Revel Casino in Atlantic City, NJ. Minakov knocked out Ron Sparks and Ryan Martinez in succession to emerge victorious from Bellator's 2013 Summer Series and secure a title shot against Volkov, who sits an undefeated 3-0 thus far in his Bellator career.
Bellator 109 takes place seven days later at the Sands Casino Event Center in Bethlehem, PA. Joining Shlemenko (48-7) and Marshall on the card are season nine's lightweight and welterweight finals -- Will Brooks vs. Tiger Sarnavskiy and Rick Hawn vs. Ron Keslar -- along with the Bellator debuts of former UFC fighters Matt Riddle and Terry Etim, who take on Nathan Coy and Patrick Cenbole, respectively.