Jackson (elbow/appendix) has made two appearances for the Athletics thus far during Cactus League play, covering two scoreless innings and striking out a batter while giving up one hit and one walk.
When healthy, Jackson was one of the Athletics' top relievers last season, but he didn't make any appearances after May 16 due to a right flexor tendon strain. He began a minor-league rehab assignment in late July, but he ultimately wasn't activated from the 60-day injured list after he required an emergency appendectomy. Jackson appears to have made a full recovery from the appendectomy and should be in good shape to make the Athletics' Opening Day roster, but it's unclear if he'll be a part of Oakland's unsettled closing situation.