Marshall, 23, never pitched for the Cubs. He was claimed in December off the Yankees' roster. The right-hander did appear in three games last season with New York.
Raley, 25, a sixth-round pick in 2009, has appeared in 14 games with the Cubs over two seasons. He was used as a starter in '12 with the big league team but pitched in relief last season, compiling a 5.14 ERA in nine games.
The 31-year-old Hammel posted some of the best numbers of his career in 2012, going 8-6 with a 3.43 ERA in 118 innings over 20 starts for the Orioles. He was Baltimore's Opening Day starter in 2013, but he took a step back last season, finishing 7-8 with a 4.97 ERA in 139 1/3 innings over 26 appearances (23 starts). Part of the problem may have been injury, as Hammel was on the disabled list because of tenderness in his right forearm.
From 2009-11, Hammel proved to be a durable back-of-the-rotation starter with the Rockies, throwing at least 170 innings in each of those three seasons while posting a 27-30 record and 4.63 ERA, inflated by hitter-friendly Coors Field. Overall in parts of eight big league seasons with the Rays, Rockies and Orioles, the right-hander has gone 49-59 with a 4.80 ERA in 989 1/3 innings.
McDonald, 29, was limited to six games last season with the Pirates because of shoulder issues, and he posted a 2-2 record with a 5.76 ERA. The right-hander was designated for assignment in September and outrighted to Triple-A Indianapolis, but he refused that assignment and elected free agency.
In the last two seasons, the Cubs have signed free agents Paul Maholm and Scott Feldman and then flipped them at the Trade Deadline for prospects. If Hammel and McDonald have success, that may be their fate as well.
The Cubs enter Spring Training with Jeff Samardzija, Travis Wood, and Edwin Jackson set for the rotation. Hammel and McDonald would be competing for spots with Jake Arrieta, Chris Rusin, Justin Grimm and Carlos Villanueva. Pitchers and catchers report on Thursday.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.