Beckett with throw an extended side session Tuesday, then face the Mariners in Seattle on Friday. The start will also allow Jon Lester an extra day of rest.
"I think he feels pretty good about himself," Francona said. "He just wants to have a day where he can go throw his offspeed pitches and have an extended bullpen."
Against Syracuse on Saturday, Beckett pitched four innings, giving up three runs on five hits, while striking out three and walking one. On an 85-pitch limit, Beckett threw 81 pitches, 51 for strikes.
"I actually thought statistically my worst inning was the best I felt, just with the game coming to me," Beckett said. "My curveball early in the game, I was trying to make it happen instead of let it happen. In the third and fourth inning, I felt my breaking stuff was really good."
In his first rehab assignment with Pawtucket on July 11, Beckett pitched four innings, giving up one run on two hits. Beckett has been on the disabled list since May 19 with a lower back strain.
"I told them from my standpoint as far as the buildup goes, I felt like I threw 80 pitches [Saturday] and I still had gas in the tank," Beckett said. "We're still building up. We don't want to push the envelope too much."