Usually it's Henderson, when he plays as the nominally right-sided midfielder in a 3. Or, if there's too much ground to make up, Gomez/Konate as right-sided CBs.
With Henderson & Bajcetic both out the line-up is anyone's guess though.
If Klopp sticks with 4-3-3 then the ones he trusts most are Fabinho, Milner & Elliott.
Unless Real score in the first half hour I could see a 4 striker formation (Salah, Jota, Gakpo, Nunez) at some point, if not from the start - with Milner & Fabinho give the enviable task of minding the fort.
Midfielders: Fabinho, Milner, Keita, Oxlade-Chamberlain, Jones, Elliott
Forwards: Firmino, Salah, Jota, Gakpo, Nunez, Carvalho
Scanning through the odds I'd reckon Milner @ 4/1 is the best bet, as he'll probably start and play 65+ mins.