Robertson started on the bench for Liverpool's 3-2 defeat at Bournemouth on Saturday evening. He was introduced at half-time in place of Milos Kerkez, with Slot admitting the former Cherries left-back wasn't fit enough to play more than an hour at most.
The Liverpool boss was asked post-match if he could afford to lose Robertson this month and if he wanted him to stay. Slot replied: "I think I need all my players. Robbo had to come in at half-time, in my opinion. I always knew that for Milos, another 90 minutes against a very intense Bournemouth side was not a possibility for him, so I knew I would have to bring (Robertson) in.
"I had already had one substitution in the first half, then you only have two moments left, so I thought 'let's bring Robbo in at half-time to make sure Milos stays available for the rest of the season'.
"There's a lot of games to be played with the players available. I have to manage that as well. The last thing we could need right now is another injury."
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