MIAMI -- Anthony Rizzo sat out Thursday's 4-2 series-opening loss to the Marlins with tightness in his lower back that the Cubs first baseman said was different from the discomfort he experienced earlier this month.
On June 10, Rizzo was scratched from the Cubs' lineup in Atlanta, but only missed one day.
"This is totally different than it was before," said Rizzo, who may need more than one day to heal. "We're just being smart and being cautious about it."
Cubs manager Joe Maddon said he could tell Rizzo was bothered by his back on Wednesday in the series finale against the Cardinals at Wrigley Field. With the Marlins starting a left-handed pitcher, Wei-Yin Chen, on Thursday, it was a good time to give the first baseman time for treatment.

"From our perspective, it's a day to day situation," Maddon said.
• Albert Almora Jr. was one of a few Cubs players who had a chance to sleep in their own bed on Wednesday night. Almora grew up in Hialeah, Fla., and spent the night with his parents. This is a special trip for Almora, whose father is receiving treatment for prostate cancer. Albert Almora Sr. has three more days of radiation treatments, his son said.
As Almora drove to Marlins Park for Thursday's game, he passed ballparks that he played at or trained at. He did work out at the Marlins' park during a tryout two days before the 2012 Draft. However, the Cubs selected him, and Almora was the sixth player taken overall.
"You have all those memories, good and bad, of what you've done," Almora said. "Now, to be able to play in a big league ballpark, it's cool -- and in my hometown."

Being home does require some juggling of his time. He estimated that he'll need 115 tickets for the four-game series to accommodate family and friends.
"There will be a lot of people," he said.
• Joe Nathan, 41, whom the Cubs signed to a Minor League contract on May 17, was to begin a rehab assignment on Thursday with Double-A Tennessee. Nathan appeared in one game with the Tigers last season, and then needed elbow surgery. His last full season was with Detroit in 2014, when he compiled a 5-4 record, 4.81 ERA, and 35 saves in 62 appearances.
• Tommy La Stella, on the disabled list with a right hamstring strain, was expected to begin a rehab assignment Monday, but there was no timetable for when Jorge Soler, on the DL with a left hamstring strain, would begin one. Both La Stella and Soler have been taking batting practice with the Cubs for a few days.

• Adam Warren, who was optioned to Triple-A Iowa to get stretched out so he could start before the All-Star break, was expected to start for the Minor League team on Saturday. Warren threw 51 pitches in a relief appearance on Sunday. The Cubs plan to go with a six-man rotation in order to give the other five a breather.
• The Cubs and Class A South Bend team have extended their Player Development Contract 2 1/2 years before the original contract expires, and the new deal will continue the team's affiliation with the big league club through the 2020 season.