Jeff Samardzija

The Chicago Cubs have traded starting pitchers Jeff Samardzija and Jason Hammel to the Oakland Athletics for a package of four prospects.

The trade will be announced Saturday and reports say the Cubs will receive the A’s top two prospects in shortstop Addison Russell, 20, and outfielder Billy McKinney, 19. The Cubs also will receive Triple-A Sacramento pitcher Dan Straily and a player to be named later.

Russell was ranked as the No. 14 prospect in baseball entering 2014 by Baseball America. He was batting .333 in 13 games at Double-A Midland after missing most of the season because of a hamstring injury.

McKinney was the A’s first-round pick in 2013 and was batting .241 with 10 home runs and 33 RBIs at Class A Stockton. Straily was 10-8 with a 3.96 ERA in 27 starts for the A’s last season and was 4-3 with a 4.71 ERA at Sacramento.

The 29-year old Samardzija, who had a 2.83 ERA, can become a free agent after 2015 and became a trade chip after he and the Cubs couldn’t agree on an extension.

Billy Beane and Theo Epstein strike the first blow of the trading season. The A’s, who have the majors best record (53-33), were seeking to upgrade their starting pitching, while the Cubs keep stocking their farm with high profile prospects.

The Cubs now have three of the top 14 players in Baseball America’s top-100 prospect list and six of the top 41.