"I can not say a lot about it", Klopp told Sky Sports.
Barcelona is looking for a replacement for Neymar, who was sold to Paris Saint-Germain for a world-record fee of 222 million euros ($262 million) last week.
"I have a bit [of sympathy] for him, he's not a bad kid".
The German added to Sky Sports: "I am responsible for the whole team, all the players, so I need to be focused on the players who are available". Positive things aside, Liverpool are missing a handful of players to face the Hornets. Good for a bout of deja vu, Watford forward Stefano Okaka punished some poor defending from a corner to open the scoring before Sadio Mane equalized with a sublime finish following good work from Emre Can to play the Senegalese attacker in to space. We passed but couldn't see what we actually wanted.
Liverpool showed familiar defensive weaknesses after conceding a trio of soft goals including a stoppage-time equaliser in an absorbing 3-3 Premier League draw at Watford.
"But for us different things are important, the physicality in the beginning - not ready for these things. I was not properly fit and I came back late and I got an injury - it was not ideal", he told the club's website. The South American is also a doubt for the midweek Champions League match against Hoffenheim.
"You'll have to ask the club".
Watford were good value for their lead at half-time and looked comfortable at the start of the second-half, only for Heurelho Gomes to bring down Mohamed Salah and give away a penalty. "I was not happy in the first half with the situation; it was very physical and Watford were too often the winners in these situations", he said.
All of the three goals they conceded came from set-pieces: two from corners and one from a throw-in.