Republican held US Senate seats up in 2020 Democrats need to win to regain control of the US Senate.

Democrats need a net gain of 4 seats assuming they don't win the 2020 US Presidential Election.
Two Democratic held US Senate seats up for re-election in 2020 that is likely to go Republican.
AL(Jones-D) If anyone but Moore-R is the Republican Nominee.
MI(Peters-D) if Trump wins the popular vote in MI.
Six Republican held US Senate seats up for re-election in 2020 that is likely to go Democratic.
CO(Gardner-R)Hickenlooper-D
AZ special(McSally-R)Kelly-D
NC(Tillis-R)Cunningham-D
ME(Collins-R)Gideon-D
IA(Ernst-R)Greenfield-D
GA(Perdue-R)Tomlinson-D