Crisp injured the finger on a fail steal attempt of third at Baltimore April 8.
"They did take [the splint] off and they manipulated [the finger] and he's not ready to [train without it]. He needs to keep this one on. They are going to give him one so he can be a little more mobile," said the Sox manager.
Francona indicated that the club would examine the finger thoroughly when they return from the trip.
"We're not going to bring a kid that's been in a splint for three weeks and put him in a game. He'll hit off a tee, then soft-tossing [batting practice] and that progression will lead up to him playing in games."
Roster juggling: To no one's surprise, Adam Stern was optioned to Triple-A Pawtucket in order to get the young outfielder more at bats. Taking Stern's place is Willie Harris, a versatile utility player who can play the infield and outfield.
"We actually talked to Adam last night, but we weren't going to announce it until today. We didn't want Adam to show up and [be surprised], and Adam kind of knew we were going to do this.
The Red Sox were required to keep Stern on the 25-man roster through April 17 to meet Rule 5 requirements. He batted .188 with one double and four RBIs in nine games, mostly seeing action when Crisp went to the disabled list.
"This is what he needs to do," Francona said. "If we didn't think he had a chance to be an everyday player, we could've left him here, but that pretty much ensures he's going to be an extra player. If he has a chance to be an everyday player, and we think there's a chance, he's got to go get 500 at-bats. And he hasn't been a Triple-A, besides the rehab stuff. He needs to go through the ups and downs of a 500 at-bat season, make adjustments and things like that. It'll be good for him."
Harris, who earned a World Series ring with the White Sox and scored the only run in Chicago's Series Game 4 clincher, signed a Minor League contract with the Red Sox on Feb. 1. The 27-year-old has a career .242 average in 174 big league games.
"If I play well and Coco comes back, someone might say, 'Hey, let's trade for Willie.' You never know. You've just got to know your role and your abilities and make the most of it," Harris said.
Harris says he will prepare himself for every possible situation.
"The scoreboard dictates everything. If we're trailing, 2-1, and Big Papi comes up there hitting, there's a good chance I'm running so I know to get loose even before he gets up to hit. Being in that situation the last couple of years, I kind of know how to handle coming off the bench," Harris said.
"I thought Willie did a good job," Francona said of Harris, who batted .161 with a homer and four RBIs in 14 games with Pawtucket. "He had a pretty good spring and we sent him down and he really handled it well. It's funny because his batting average wasn't real good and he admitted it wore on him a little bit. But talking to [Pawtucket manager Ron Johnson], he was professional, upbeat in his attitude and he hustled. The at-bats will be good for him.
"Now hopefully, he comes up here and hopefully gives us a little energy, a little boost when he plays."
With Stern now in Pawtucket, Francona said Thursday he will use a combination of Dustan Mohr, Willie Harris and possibly Wily Mo Pena in center until Crisp returns.
"The days Wily Mo plays right are probably the same days Dustan plays center so we'll see," Francona said. "We were kind of using Stern and Mohr to play center and I can see us using Willie Harris and Dustan to compliment each other.
"If Willie gets at-bats the way Stern was, where they're somewhat sparingly, Willie is somewhat used to doing that and that's his job. And there's kind of a big difference there between Adam doing it and Willie."
All's not Wells: David Wells did not have the best of days Thursday. He attempted to play catch and test out his sore right knee.
"Played catch a little today. I got through it but it was very uncomfortable," said the 43-year-old lefty, holding court in front of his locker before Thursday's game.
Wells, who went on the DL after his only start April 12, received his second shot Thursday to help lubricate his knee. Wells said he plans to get at least three shots before he and the club re-evaluate his condition.
"I'm getting another shot [Thursday] night and then we'll wait 48 hours before I do anything," Wells said. "After the next one, I'll see how it goes."
"He'll just stay back and do his work while we're gone," added Francona.
Coming up: The Red Sox open a three-city, nine-game road trip when they open a three-game series against the Blue Jays at Rogers Centre. Josh Beckett (3-0, 1.29) goes to the hill for Boston, looking to stay perfect, while Toronto counters with A.J. Burnett (0-1, 6.00), making his second start. The pitchers were teammates last season with the Marlins.