We do agree, unfortunate as it may be.
The contract agreement would come after, also with the start date as agreed by the clubs. In short, we could theoretically agree a deal with both BVB and Haaland for January 2024 if we wish. Dates are absolutely not a blocker, it’s just rare because things change quickly. Huge risk for the buying club’s finances (as covid has shown), and a risk for the player (UCL qualification etc).
There’s nothing stopping us agreeing a deal now, for summer. On paper.
That is still a transfer between clubs. Not a player agreeing a pre-contract.