Of the two the bigger name is Jeremy Hermida, an eight-year MLB outfielder as a member of the Marlins, Red Sox, A's, Reds and Padres. He's a career .257/.334/.415 hitter but has struggled to find time in the majors in recent years, falling from being an everyday player from 2007-09 to making just 13 MLB appearances with the Padres in 2012. He spent all of 2013 with the Indians' AAA affiliate, batting .247/.365/.416 with 17 home runs.
Hermida was the #11 overall pick in the 2002 draft and in 2006 Baseball America listed him as the #4 prospect in all of baseball. He's still just 29 years old, and will turn 30 on Thursday.
The other signee is infielder Joe Thurston, a 31-year-old seven-year MLB veteran perhaps best known for playing in 124 games as a member of the Cardinals in 2009. He's only played in one MLB game since, as a member of the Marlins in 2011. Thurston is a career .226/.305/.323 hitter in the minors and is primarily a second baseman. He split 2013 between independent ball and the Mexican Leagues, hitting .297/.390/.422 in 561 plate appearances, and is 34 years old.
The Brewers did not specify if either player received an invitation to major league spring training in Maryvale, but I wouldn't be surprised to see both of them there.
UPDATE: @Mass_Haas confirms:
#Brewers own transaction and roster pages now indicate that IF/OF Joe Thurston and OF Jeremy Hermida did receive big league camp invites.— Jim Goulart (@Mass_Haas) January 26, 2014