Removal of the grass is scheduled to start on Thursday and the turf will be ground up and composted, then a thick layer of sand will be excavated. Once the area is cleared out, it will be laser-leveled and prepared for the new grass to be installed over several days at the end of October.
The new grass will be from Country Green Turf Farms outside of Olympia, Wash., which was the original supplier of Safeco Field's grass as well.
The dirt areas of the infield and pitchers mound will also be replaced with about 260 tons of clay trucked in from Salt Lake City, Utah.
The Mariners say the project will lower the elevation of the field about four inches, back to its original level. Over the years, the field has gradually risen while being "top-dressed" with sand, a common landscaping practice that is used to create a smooth surface and promote healthy growing conditions.
The new infield dirt is expected to be installed by Oct. 23, and the grass should be in place by Oct. 31, with the pitcher's mound the final item to be completed by March, all in plenty of time for the facility to be ready for Opening Day on March 29 against the Indians.
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB. This story was not subject to the approval of Major League Baseball or its clubs.