Hjelle will be recalled from Triple-A Sacramento prior to Sunday's game against the White Sox, Evan Webeck of The San Jose Mercury News reports.
Hjelle will return to provide length behind starter John Brebbia, who has not pitched more than two innings in an appearance this season. The 6-foot-11 Hjelle pitched five scoreless innings for Sacramento his last time out June 26, allowing two hits while striking out six.