Mary Ann Lang, the mother of his wife, Jacque Francona, passed away from complications related to cancer, said bench coach Brad Mills, who will manage the Red Sox in Francona's absence.
"They were hoping that [Lang's passing] was going to be much later, but the last few weeks, she went downhill kind of quickly," Mills said.
Francona was informed of his mother-in-law's passing following Monday night's game in Minnesota and he accompanied the Red Sox on their scheduled flight to Baltimore. On Tuesday morning, he flew to Boston to pick up daughters Leah and Jamie for a flight to Dallas, Texas, where they were to meet daughter Alyssa and son Nick before continuing on to Tucson.
Mills was unsure when the funeral would be held but said, "Terry's hoping to be able to come back Thursday night."
Francona's absence hit the Red Sox in a very personal way, said right-handed reliever Mike Timlin.
"We feel for Terry. He's part of the fabric, part of our team, part of what we do here every day," Timlin said. "He lost someone personal to him ... and as much as we try to keep personal things from coming into this room, they do."
Sitting in Francona's usual office -- the door was opened and lights were turned on only to accommodate the media's daily pregame meeting with the temporary manager -- Mills expressed sadness at the turn of events that precipitated his promotion.
"It's never nice, especially in this situation and under these circumstances," said Mills, Francona's bench coach for the past five seasons, his first-base coach for four years in Philadelphia and a former University of Arizona and Expos teammate of the current skipper. "I would probably say it's never nice under any circumstance when it's something [bad] that's happened. I guess it is a little bit different when it's a graduation or something along those lines."
Mills went 5-3 while filling in for Francona during the 2005 season, when Francona missed four games because of a viral illness, three more due to suspension and another to attend a graduation ceremony for one of his children. Mills said he's always prepared to manage if needed, but he left no doubt that he's just as happy to serve as a trusted lieutenant.
"I'm ... a bench coach now and I want to be the best bench coach I can be for Terry and the Red Sox," said Mills, adding that other members of the coaching staff have pitched in to create as "normal" an atmosphere as possible.
Constant in-game discussions between Mills and Francona have prepared the bench coach for spot duty.
"Sitting next to Terry, you're able to get feedback from one another and kind of know what he's thinking, as well. It's always helpful in situations like this," Mills said, "He'll ask my opinion on some things -- and not necessarily use them, because he's got his opinions -- and there's times I'll interject if I feel there's something. ... There's always some give and take when you're talking back and forth. The conversation's what's good."
Because Mills and Francona have developed a symbiotic relationship, Timlin doesn't expect any problems with the unexpected managerial change.
"Brad has a different way of managing, but it's not going to be a drastic change for us," Timlin said. "He's been around Terry for a long time. It's more or less a seamless transition."
Said Mills: "These guys are a veteran ballclub. We're not going to reinvent the game. ... The dynamic's going to stay the same."
So is the goal.
"We want to play well and make Terry feel better about not being here. ... That's the best thing we can do to help him," Timlin said.
Pete Kerzel is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.