Slot has spoken in his press conference ahead of Liverpool's Premier League meeting with Aston Villa on Saturday night as the Reds look to continue their 12 game unbeaten run at Anfield.
The Dutchman opened up on the topic of Tsimikas and Robertson who are fighting for the same position.
“I think my line-ups tell you what I think about this – I think we have two very good full-backs and we play many, many, many games. I think both of them need their games because it's also a position where a lot of effort is being asked. If you look at the players that have played most games, it's mostly our centre-backs and they don't run the most if you compare that to full-backs, midfielders or wingers.
“There are multiple reasons why our full-backs or midfielders are sometimes rotated, but definitely also has to do with the quality of the players. For me, I have two very good left full-backs and Kostas has started a few times. Let's see who starts on Saturday.”
Tsimikas started against Bayer Leverkusen in midweek as Liverpool continued their unbeaten streak in the Champions League which likely means Robertson should start on Saturday but with the pair in fierce competition it is unclear who will make it on to the teamsheet.