The Poland international joins in a €7m deal.
"Lukasz is a centre-forward with a great deal of experience," Udinese technical director Daniele Pradè told RMC Sport.
“He can hold up the ball for his teammates, run the front line himself and attack the space too. He is strong physically and mobile along the attack.
“He's got a sense for the goal and makes his presence felt in the penalty area."