Their competition extends far beyond the football field.
"If we’re just walking down the hallway, I call him, 'Little guy,' 'cause he’s little," Caper said.
The 5-foot-11, 215-pound Caper has two inches and about 20 pounds on Baker, but Baker has a compact, sculpted frame, earning the nickname "Rock." That brings up another frequent debate between the two backs: Who's stronger?
"He’s pretty strong," Caper admits, before adding, "He thinks he’s stronger than he is."
Baker makes it clear: "I'm stronger."
For most of us, the constant competition would get a bit tiresome, even if most of it is friendly in nature. But Caper and Baker would have things no other way.
The two sophomores chose to room together at Michigan State and intend to do so for the remainder of their college careers. They will compete for carries this fall -- head coach Mark Dantonio wants to divide things 50-50 or as close to it as possible -- and possibly for the next two seasons as well.
"That’s going to be my roommate for the next three years," Caper said, "One and two, me and him, Cape and Bake."
After losing All-American Javon Ringer following the 2008 season, Michigan State used a committee of backs last fall, as four players recorded 40 or more carries. Caper led the way with 120 carries for 468 yards and six touchdowns, and Baker followed with 85 carries for 427 yards and a score.
The Spartans ranked second in the league in passing but just sixth in rushing and ninth in rushing attempts with 419. The coaches expect things to balance out this fall, in large because because both Caper and Baker have a year under their belts.
The two players bring different styles to the backfield. Caper is a pure power back -- head coach Mark Dantonio likened him to former Iowa star Shonn Greene -- while Baker describes himself as "somewhat power [back], somewhat scat back," and adds, "real quick."
"His initial from A to C is just tremendous," offensive coordinator Don Treadwell said. "He just has that burst, but he also has a lot of strength with that, a very compact build."
Caper had a nice stretch early in Big Ten play last fall, scoring the game-winning touchdown in overtime against Michigan and following with 158 rushing yards and two touchdowns in wins against Illinois and Northwestern. Baker played in the opener before missing five games with an injury. (He underwent knee surgery in high school.) He started in place of Caper against Western Michigan and recorded 78 rush yards on only 15 carries.
Baker finished his freshman season with his best performance, rushing for 97 yards and a touchdown on only 12 carries against Texas Tech in the Alamo Bowl.
"Both those young men, you could see a difference even from the regular season to the time we played Texas Tech in the bowl," Treadwell said. "They were understanding where to hit the hole, 'What’s my footwork? What am I supposed to be reading?' And it showed itself. Now you spin it forward into spring football, and you see it even more.
"They’re a tremendous duo."
Treadwell calls the running backs "good friends" and notes that it's not always the case with two strong competitors.
Baker has some extra motivation the season after being snubbed in Michigan State's player draft for the spring game. Caper was the first running back drafted, but next came freshman Le'Veon Bell, not Baker.
Then again, Baker doesn't need to prove much to the team. Just his roommate.
"We compete at everything," Baker said. "That's how we want to get better."