"I need to be a little careful saying that," Francona cautioned, "because I don't want to push somebody to do something they're not supposed to. So, I don't say that very often, but I watch him walking around, and I talk to the trainers. It wouldn't shock me [if he returns before season's end].
"Again, I don't want to create unrealistic expectations for him, and put him through that, but if it's at all possible, he'll do it."
Masterson, who suffered a strained left oblique in his start against the Orioles on Sept. 2, described his situation as "status quo" prior to Monday night's game against the Royals. The right-hander continues to undergo treatment for his ailing left side, and hopes to be cleared to resume playing catch at some point during the Indians' upcoming series in Chicago.
Cleveland opens a four-game series with the White Sox on Thursday and, if given the go-ahead, Masterson plans on attacking his rehab more aggressively over the weekend.
"It's really great and it's not tedious whatsoever," joked Masterson, referring to his current rehab routine. "But it does help. Each day, it continues to feel better and that's what you want to have, as far as the feeling goes. I haven't overly tried to test it, because it's better to take it nice and easy at first and be aggressive once it's all the way out of there."
On the season, Masterson has already established career bests with 14 wins and 188 strikeouts, and he has posted a 3.52 ERA in 189 1/3 innings.
Masterson believes he will be able to add more innings to that total before the end of the season.
"Why not?" Masterson said with a grin. "Positive thinking definitely helps the process. It's just the fact of the way I felt when it took place. Sometimes, some other people have much different feelings, much more pain. That's why I feel a little bit more like, 'Hey, we could have this.'"
Jordan Bastian is a reporter for MLB.com. Read his blog, Major League Bastian, and follow him on Twitter @MLBastian. This story was not subject to the approval of Major League Baseball or its clubs.