Francona said the work Santana has put in behind the scenes is more important than what onlookers observed during the infield practice.
"From the minute we have laid eyes on him, he has been nothing but diligent," Francona said. "I mean, staying at it to the point where he's taking a weird-sided, crazy super ball back to his room at night to work on side to side. He has worked so hard just to get to this point.
"I'm so proud of him already just for what he's done. It's going to be interesting going forward."
The rubber ball Francona mentioned has a handful of bumps that make the direction of its ricochet unpredictable when thrown. Entering the spring, Santana had already logged roughly 30 games at third base during winter ball in the Dominican Republic.
"He's very athletic," Francona said. "And he's aware that, just because he wants to play third, doesn't mean he's going to play third. We have a responsibility to our team to put our best team on the field. That's what we're going to do. The fact that we're talking about this with Carlos is a huge compliment to him."
As for Chisenhall, whose career in the big leagues has been riddled with inconsistency, Francona said the third baseman understands the situation.
"[I told him] the truth, which is that we're a better team with him on it, we believe," Francona said. "But we want him to earn it. That's being very truthful. I think he kind of agrees with it. If players play well, and they're good, we'll find places for them."
Jordan Bastian is a reporter for MLB.com. Read his blog, Major League Bastian, and follow him on Twitter @MLBastian. This story was not subject to the approval of Major League Baseball or its clubs.