Zobrist, 36, has been battling the injury for several weeks, forcing the switch-hitter to bat only left-handed. The Cubs were hopeful a few days off would help him heal up completely, but he'll need more time.
"I think we're going to try and do some imaging [MRI] just to see if there is anything going on in there," Zobrist said Friday afternoon. "It's inflammation that hasn't gotten better because I've been playing through it for the last two weeks plus."
Zobrist began the month hitting .242 but is down to .223 after going 0-for-4 on Monday. That's the last time he played.
"If it's going to take another three-four days, we're getting close to 10 days anyway," he said. "It probably needs total rest."
La Stella, 28, was in the starting lineup for Friday's game against the Pirates after being recalled. He had a 1.006 OPS in 16 games with the Cubs this season before being sent to the minors. Meanwhile, there's still no timetable for pitcher Kyle Hendricks' return, as he's on the DL with tendinitis in his right hand.
"It's just sore," Cubs manager Joe Maddon indicated. "We don't have a finish line in mind yet. It's just not going away. We don't want to push him on it."
Zobrist headed to DL with wrist injury
Ben Zobrist discusses why the Cubs decided to place him on the disabled list and how the team plans to monitor his wrist injury.