2. Sarri is not looking for a conventional striker
Back in his days with Napoli, the Italian manager used a front three that had no strikers, and he had a lot of success. He used Lorenzo Insigne in advanced roles, a move which turned out to be alarmingly effective.
Sarri played Hazard up front for a few games, and Hazard managed to find his name on the scoresheet as well. However, Pedro's injury has seen the Italian manager move Hazard back to his original position.
With Hazard being known to prefer his position on the left flank, this could mean that Pulisic would find himself attack through the middle for the Blues. His pace combined with that of Hazard and Willian/Pedro could be a lot for the opposition to handle, and with none of them being a centre forward, they could freely move and interchange at the front, causing headaches for defenders. Due to the dearth of quality strikers in the market, this could be the route that Sarri is looking to take.