Lucas Erceg, Oakland A's - Traded to Royals
The former Brewers prospect has made a name for himself in the Oakland bullpen. He's drawing significant interest and has several years of team control left. Erceg has a 3.68 ERA this year and could help fill the gap with so many injuries in the Brewers bullpen.
Milwaukee has a lot of bullpen options, but with Trevor Megill going on the shelf for an unknown period of time, perhaps adding another arm wouldn't be the worst idea.
Update: Erceg has been traded to the Kansas City Royals
Jack Flaherty, Detroit Tigers
Jack Flaherty was scratched from his start on Monday night because the Tigers were expecting to trade him. A trade did not materialize on Monday but it's likely one will happen on Tuesday. Perhaps teams balked after the Astros paid a high price for Yusei Kikuchi and will try to take it down to the wire, hoping the price falls at the last minute.
Flaherty has a 2.95 ERA this year and is the top rental starting pitcher on the market. The Brewers have the capital to acquire him if they want to.
Cal Quantrill, Colorado Rockies
An under the radar starting pitching option the Brewers could instead pivot to is Cal Quantrill. He's had a solid season in Colorado and the Brewers have already made one trade with the Rockies. Quantrill has a year and a half of team control remaining.
Michael Conforto, OF, San Francisco Giants
The Giants are selling. Late on Monday night, Jorge Soler got shipped to the Atlanta Braves, and Conforto could be the next to go. A left handed bat, Conforto would be the closest thing to a replacement for Christian Yelich the Brewers could find on the trade market.
Conforto isn't having his best season, but he has 10 homers, a .710 OPS, and a 104 OPS+. He's due the remainder of his $18MM salary this year (approximately $6MM) and is a free agent at season's end, so he's a pure rental bat that can provide left handed power.