Zobrist felt good enough to go through some activity Monday afternoon at Tropicana Field.
"Played some catch, hit off the tee, and felt great, felt normal -- pretty much all of the normal moves I would make out on the field in a controlled environment," Zobrist said. "So tomorrow, get out on the field, take ground balls early, hit on the field early and make sure everything feels good. And if it feels good, then I'm hoping to be in there."
Zobrist did not feel like playing on the artificial surface at Tropicana Field contributed to his injury.
"I did it swinging," Zobrist said. "Swinging is the most violent activity I'm going to put on my lower back. Once I can take full hacks, [I'll be ready], and I took some really hard ones off the tee today. So hopefully, by [Tuesday], everything will feel completely normal and I'll be able to really let it fly."
If Tuesday doesn't work out, Zobrist believes Wednesday will be the date for his return to the lineup.
"For me, I'm thinking definitely Wednesday," Zobrist said. "Obviously, they want to be careful, so we'll see how it goes. But I'd like to be ready to pinch-hit soon, even in a couple of hours if they'll let me."
Maddon reported that Pena is progressing nicely as well, but did not have an estimated time for his return.