I would be surprised if the Brewers do anything at the deadline. Teams are not allowed to scout at the alternative sites so you have no idea what is happening at those sites. Twenty teams in baseball are sharing data and video from their alternative sites, however the Brewers opted not to join that group of teams. I haven't heard any team announce any injuries from their alternative sites so you would be flying blind as to what is happening with other teams.
Another thing working against the Brewers is money. They will be fine this year, but next year is going to be ugly. I read in the Athletic that teams are expected to cut payroll for next year by 20 to 30 percent. Next year they will have to pay the players for the entire season and it's highly doubtful that attendance will be back to pre Covid levels. Heading into next year the Brewers have only six players under contract(Yelich, Cain, Garcia, Peralta, Lindblom, and Suter) and that accounts for 57 million. It's really hard to see them adding additional financial commitments. The Brewers also have the worst farm system in baseball. That's according to Baseball America, Fangraphs, MLB Pipeline, ESPN, and the Athletic. So basically everyone agrees that the Brewers farm system is the worst in baseball. That makes it really hard to pull any deal off when you don't have much to offer and no one has seen those guys play since a few brief glimpses in March. After this year Josh Hader will have three years of control. His salary through arbitration will be roughly 7 million for 2021, 12 million for 2022, and around 16 million for 2023. At those numbers, less than 10 teams are going to be able to afford him. Teams that would be trading for him know this and are going to low ball the Brewers for him. The teams that can afford him aren't going to overpay for 60 innings in a full season. The Brewers are not going to get anything close to his value if they trade him.
If you want to drink all day, you have to start in the morning.