Texas activated Fujikawa before the series finale against Kansas City, and he pitched a scoreless eighth. He retired all three batters he faces.
Right-hander Spencer Patton was optioned to Triple-A Round Rock to make room on the Rangers roster.
Fujikawa was signed as a free agent last winter. He was placed on the disabled list before the season because of a right groin strain.
The 34-year-old reliever had a 3.86 ERA in 10 relief appearances for Round Rock.
Fujikawa signed with Texas after spending the last two seasons with the Chicago Cubs. His time with the Cubs included a 14-month layoff following Tommy John surgery.