Although Lewandowski has reached an agreement with Barcelona to stay with Barcelona until the end of the season or one more season. But Barcelona must move quickly to find a replacement, Barcelona is currently eyeing Newcastle United striker, Alexander Isak, and Viktor Gyokeres from Sporting CP is a more affordable option with a cheaper transfer value.
Barcelona management will not take the risk too quickly to find a replacement for Lewandowski in a financial condition like this. As long as Lewandowski can still be relied on, Barcelona management will look for a replacement player with an easier option such as a player who has free agent status. And in my opinion if Barcelona is eyeing Alexander Isak, it is just a rumor. On the one hand, Newcastle will not release the player at a cheap price and while Newcastle currently still needs the player. So at this time Barcelona can only survive with the existing players and look for a replacement player slowly without rushing which can put more pressure on Barcelona's finances.
Barcelona financial condition has not fully improved, they are more inclined to bring in free transfer players rather than making big recruitment to find a replacement for Lewandowski. If they were forced to do so, Alexander Isak's name would be at the top of the list, but Newcastle will not let their star man go on the cheap. Alexander Isak also did not rule out the possibility of moving from Newcastle, he is very interested in moving to Liverpool. In my opinion, Barcelona chances of getting him are very small.