Manager Mike Hargrove says Jacobsen will take batting practice every other day instead of every day. He'll ride an exercise bicycle to keep up his conditioning.
The 6-foot-4, 270-pound designated hitter had cartilage surgery on his right knee last September. As a rookie with the Mariners last season, Jacobsen hit nine home runs and had 28 R-B-I's in 42 games after being called up from Triple-A Tacoma. He hit 26 homers and had 86 R-B-I's in 81 games last season for the Rainiers.
The 29-year-old came to spring training hoping to replace the retired Edgar Martinez as Seattle's D-H, but Raul Ibanez seems to have the job.
The Mariners say outfielder Chris Snelling will undergo surgery to repair torn cartilage in his left knee.
He is expected to be out for six weeks.
It's the same knee that suffered a torn ligament during the 2001 season.
The 23-year-old Australian had an MRI last week and the results were announced today.
Snelling missed all of last season because of surgery to his right hand.