That is something that is easliy done using a pivot table. Insert, Pivot table Drag the Team field to the rows area Drag the Min/Row field to the sigma area Right-click the min/row column in the pivot table and choose "Summarize Values By" and select "Average". Done!
You may simply insert a Pivot Table and drag the Team field in the Rows area and the Min/Row field in the Values area and change the Value Field Settings to show the Average.
If you go for the Pivot Table approach, it would be better if you convert your data into an Excel Table and then insert a Pivot Table based on this table so that when you add/delete data in the table, once you Refresh the Pivot Table it will always show you the updated report.
Please refer to the attached which contains a Pivot Table solution and the formula solution as well.