Matsuzaka went in to Game 6 with just one day of rest, after giving up five hits and five runs over four-plus innings and throwing 82 pitches in Thursday's Game 5.
For Matsuzaka to be used Saturday, it would probably be an emergency situation, such as extra innings. But if the Red Sox make it to Game 7, Matsuzaka could be in line for a more significant role.
"Tomorrow, with an extra day, would really help," Francona said. "I think what we do today is maybe kind of hold him back so we can use everybody and maybe match up. I don't know if we're dying to do it, because we also have [Paul] Byrd. Who knows how you get there?"
More than anything, Francona was appreciative that Matsuzaka would volunteer for a role he hasn't performed in since 2004, when he pitched in relief for the Seibu Lions in a clinching victory in Game 7 of the Japan Series. Previous to that, Matsuzaka came out of the bullpen for Seibu in Game 4 in 2002 -- a clinching loss -- in the Japan Series.
"It's just kind of nice from where we sit, when we come out yesterday for the workout and they say, 'Hey, look, here's what I can do,'" Francona said. "You know what, in a day and age where maybe guys look at people making a lot of money, this reinforces how we feel about a lot of guys. It makes you feel good."
Aside from those two situations with the Seibu Lions, you'd have to go back to Matsuzaka's high school days find his last relief appearance. In fact, Matsuzaka became a legend pitching out of the bullpen at the famed 1998 Koshien Tournament a day after he had thrown 250 pitches in a start.
"I think you can do this from time to time," said Francona. "It's not something that you would ever do in the middle of the year, because it doesn't set up for a guy long-term. But the next thing you're really looking at is Halloween or Thanksgiving if you can win. If one of our trainers came in today and said, 'You shouldn't do this,' we wouldn't do it."
Knuckleballer Tim Wakefield, who lasted just 2 2/3 innings in his Game 4 loss, might also be available. However, the Rays have pounded on Wakefield's knuckleball the last two times they've faced him, so that might be less likely.
"We'll see," Francona said. "Some of it depends on how he feels. There could e a role for everybody."
One thing Francona was decisive about is that he's not going to over-use any of his relievers, including ace closer Jonathan Papelbon. Don't look for Papelbon to duplicate the efforts of Rays reliever Dan Wheeler, who went 3 1/3 innings in Game 2.
Though Papelbon came on in the seventh inning in Game 5, Francona said there was no chance he would have pitched as many as three innings that night.
"You have to know your guys," Francona said. "He's pitched a lot lately. No, we couldn't have done that. There is no temptation. I wouldn't do it. I couldn't do it. That was actually pushing it the other night. You can look at a pitch limit all you want, and we do. Every pitch he threw to [B.J.] Upton, you could see him taking a little more time, a little more time. He was gassed when he came out after that [eighth] inning. It's Oct. 18. That's a lot [to ask]."