"It's absolutely a step forward," Aardsma said. "It's a matter of getting over that hurdle, and it's mental now. I can push it, and I can put more on it. It's a matter of letting it go and saying, 'You know, I can do this, and it's not going to hurt me.' "
It was Aardsma's first time throwing off the mound during this stint on the DL, and Francona said his status is "pretty good," but not ready to get into a game.
"He's not experiencing pain, which is good," Francona said. "He still feels tightness, which I think is expected. Until that dissipates, we certainly won't turn him loose in a game. The last time we were in Anaheim and he threw a side, he felt real well. Then, to get in the game and try to reach back a little more, that's when he felt it."
Meanwhile, Julio Lugo continues to work on his comeback -- albeit slowly.
Lugo's severe left quad strain is keeping him from making progress baseball-wise, but he's walked throughout the clubhouse rather freely without a brace or wrapping throughout the homestand.
Still, Francona said Lugo is not at a point where he is able to do baseball activities, and he continues to participate in pool-related activities to help the recovery.
"Lugo is working every day while we're home," Francona said. "He'll go to the ballpark and do his stuff in the water -- a lot of non-weight-bearing things."
Lugo isn't at the point where he's able to go on the road trip with the team; instead, he'll likely stay back in Boston when the team travels to Kansas City and Chicago next week.
"He'll probably stay back with [Sox physical therapist] Scott Waugh," Francona said. "There's a time when ... it's good for guys' recuperative powers or their attitude to be around the team. I don't know if he's ready to do that. ... We'll see."
For Tuesday's contest, the answer was simple. Alex Cora, who went 2-for-4 with a run scored against the Yankees on Sunday, got the nod over Jed Lowrie at shortstop and hit eighth.
"The object is to keep guys sharp," Francona said. "I think playing Cora tonight is the best way to do that."