The Seagulls are reportedly close to bringing Ulloa back on loan from Leicester, where the striker was a team-mate of Knockaert for a season.
Speaking after the 1-0 FA Cup win at Middlesbrough, Knockaert said: "I've played with him, so know he's a good player.
"He's a great guy as well, so it would be nice.
"The players are just focused on football and the club knows what they need to do to get better and better.
"If he comes, he will be welcome. We have a really good team but I know Leo well and it would be nice to have him."
On Albion's win at Boro, Knockaert said: "If there was one team who was going to win the game, it was us.
"It was a good competitive game today. We knew it was important to find the winning way again and we did it.
"It doesn't matter if it was against a Championship side or not. It's always a tough place to come here and it was important to win and the confidence will be good again now."