So, naturally, the Red Sox turned to the right-hander who has handled every challenge thrown his way since being called up as a starter last season.
"[Masterson's] a good pitcher," Francona said. "It's not like you're throwing somebody out there because he can do it. This guy is good. He just has the ability to be versatile, and we're not deep enough into the season where it's a real big deal and we're worried about him. And it will help us."
Masterson came on in relief on Tuesday night, when Matsuzaka left after one inning with shoulder fatigue. Matsuzaka was placed on the 15-day disabled list the next day.
"When we brought him in early, once we got him to a certain pitch count, he could realistically go out there and give us enough of a game so you're not going through the whole bullpen," said Francona.
Masterson threw 60 pitches over four scoreless innings, the longest scoreless relief appearance for a Red Sox pitcher since Kyle Snyder went scoreless for 4 1/3 on July 31, 2006.
It was also in 2006 when Julian Tavarez nearly single-handedly saved the Red Sox's rotation by going back and forth between the rotation and bullpen.
"The one guy who did it was Tavarez," Francona recalled. "Julian was amazing at that. He could [pitch in relief] a long time, and then he'd take the ball and say, 'You can leave me out here all day.' He sucked up innings when he probably shouldn't have, but it saved our staff at times. He was amazing at times.
"A little different, but the one thing about Julian, he understood sometimes that was part of his role, sucking up innings that maybe weren't the glamorous ones that helped us win games down the road."
Injury updates: Julio Lugo (right knee) made five plate appearances and Mark Kotsay (back) made two in extended spring action on Friday.
"We talked to Craig Shipley, who was there, and [he] said everything went pretty well and there was no incident," Francona said. "Lugo ran the bases a couple of times and scored on an extra-base hit. Kotsay lined out to pretty deep center field."
John Smoltz is scheduled to make his extended spring debut on Saturday.
Jed Lowrie will wear a splint on his sprained left wrist for another five days, and he told reporters that he hasn't ruled out surgery.
"It's going to need some more time," Francona said. "Jed's a really intelligent kid, and he's got a lot of good questions, which is good. At the same time, I don't feel qualified to answer them, and when he asks questions, they make sense to me, so I'd like to sit there and listen myself. And I think [GM] Theo [Epstein] felt the same way."