"We looked at it and talked about it," Cherington said. "We haven't taken a college position player that high in a while, and he's a kid that we've known for so long -- back to high school. Typically, it's not something we do very much, bringing a draftee from the previous year into camp.
"We felt like, in this case, we knew him well enough because we had scouted him all the way back to high school, and he'd been through a lot and played a lot of baseball at a high level -- college, Team USA -- and played a premium position. We just wanted to get him exposed to the Major League staff, and felt like it was appropriate to do in this case."
Marrero will get a chance this spring to learn lessons from veteran star Dustin Pedroia, who also went to Arizona State.
This doesn't mean the Red Sox are going to speed up their organizational approach when it comes to getting prospects to the big leagues.
"I don't think so," Cherington said. "We felt he was ready to be exposed to Major League camp and be able to handle it a way that was productive, despite the fact he just joined us. We felt comfortable that way, in part, because we felt we've known him so long even though we just signed him last summer. So I don't think it's a departure from anything. It doesn't mean he's going to start at this level or that level. That will be determined at the end of camp."
The Red Sox also invited perhaps their top two position prospects to camp -- shortstop Xander Bogaerts and center fielder Jackie Bradley Jr. It will be the first Major League camp for both players.
"I think it will be fun," said Cherington. "I think both guys are pretty mature for their age and their level, and both have accomplished some things on the field. I would expect both to come into camp and be professional and treat the older guys with respect. But when they're on the field, they can do what they can do. They're talented kids. They don't need to take a backseat [to] anyone once they're on the field. It will be good for them and fun for us to see."
The club invited several veterans to camp, including outfielders Ryan Sweeney and Mitch Maier, infielder Drew Sutton and first baseman Lyle Overbay.
The other invitees are: Pitchers Pedro Beato, Chris Carpenter, Anthony Carter, Jose De La Torre, Terry Doyle, Chris Hernandez and Oscar Villarreal; infielders Jonathan Diaz, Mark Hamilton and Justin Henry; and outfielders Jeremy Hazelbaker and Juan Carlos Linares.
Sweeney, who was re-signed by the Red Sox a couple of weeks ago following a shoulder injury to Ryan Kalish, will be right in the mix for a bench spot. So, too, will Overbay, who is the most experienced first baseman on the roster.
Pitchers and catchers will hold their first formal workout on Tuesday. The first full-squad workout will be Friday.