Otte moves to Liverpool from Borussia Monchengladbach, but was also with the USA at the Copa America.
Slot explained: “He also had a tournament, he was with the USA team.
“Unfortunately for him, they went out of the tournament.
“I gave him a few weeks off but he said: ‘No, I want to come as soon as I can’. So he's already in now after one week's holiday and I think that's what you like to see. Having a holiday is important but you like to see staff members and players, that they want to come in as early as they can to join the team and help us for hopefully a very good season.”
Meanwhile, Slot has explained adding Aaron Briggs to his staff as a new 'individual development coach'.
“He’s most importantly finding the bridge between the youth academy and the first team,” he said. “Doing a lot of one-to-one meetings with the players as well and of course help us with the training sessions.
“He is just a member of our staff, maybe a bit more focussed on the players who are in between the 21s and the first team. He has an analysis background as well as being an assistant coach so we’re going to use him in every department.”