Deadline mistake to avoid #2: Banking on internal improvements from the offense
Last year, the Brewers biggest need was offense. They acquired only one position player, Esteury Ruiz in the Hader trade, and they didn't even call upon him to help the big league club. They were instead banking on their current hitters to just start hitting better. They can't make that mistake again.
The Brewers have some injured and underperforming hitters. Rowdy Tellez was in a massive slump before an injury. Luis Urias was injured early in the year and didn't perform well after getting healthy. Milwaukee cannot allow themselves to think that they don't need to get any more offensive help because they have Tellez coming back or can call upon Urias from Triple-A. Jesse Winker has been a massive disappointment.
Milwaukee needs some insurance in case Tellez, Winker, and Urias don't start hitting again. They should look to get more than just insurance, they should get a sure thing where they aren't expecting to rely on Tellez or Urias down the stretch.
The Carlos Santana trade helps address the first base position and perhaps could put Tellez out of his job when he returns, but the DH is still a possibility. Milwaukee needs help at DH and depending on Tellez for that would be a mistake. Depending on Jesse Winker to be better at that spot would be a mistake.
The Brewers cannot just stick with Carlos Santana as their only offensive addition. They need more and they need to get players that are currently outside the organization. Milwaukee's cycled through all the position player options on their 40 man roster and there isn't much there.
Going into this deadline with the mindset that the Brewers can rely on Tellez, Winker, Urias, and Brian Anderson to perform to the standard necessary when they return would be a colossal mistake that Matt Arnold needs to avoid. Get more hitters.