Top speed
Alexander Isak: 34.5 km/hr
Lewandowski: 20 km/hr
On a more serious note, if an ageing Lewa who can't run, can't pass, can't hold-up and whose first touch is a pass to the opposition can score 42 in all comps. Imagine the kind of impact a pacy and mobile Isak can do in Flick's system.
But unfortunately Barca is broke and even if top EPL clubs don't need him next summer, there will be the likes of Bayern (replace Kane), PSG (add tactical flexibility) or even Madrid (if they realize after this season they can do better with a proper 9) vying for him.
There were also rumours about Laporta wanting Julian Alvarez as his next marquee signing. As versatile and hardworking he is, I prefer the Eritrean over the former. Given Atletico's interest in Fermin, I wouldn't be surprised if they include him in a deal to bring in Alvarez next summer.
Isak to Barca is highly unlikely. But you know dreaming is free.