With forwards Luis Diaz (25) and Diogo Jota (26) both sidelined due to injury Liverpool brought in Gakpo, who scored three goals for the Netherlands at the World Cup, from PSV Eindhoven for a reported initial fee of 37 million pounds.
"I don't want to disappoint anybody but we signed an outstanding player like Cody Gakpo and the next thing you can read is, 'Who next?'" said the German.
"We cannot play like Monopoly. We never did ... It is a big part of my philosophy, working full of faith and trust with the players we have and not constantly questioning them by telling them that we need another player in their position."
After a poor start to the season, Liverpool are 15 points behind leaders Arsenal but have won their last four league games to move up to sixth ahead of Monday's trip to Brentford.
