Ryu is confident that his back issue is not serious, Dylan Hernandez of the Los Angeles Times reports. Ryu is currently fighting through a bout of mid-back tightness, which surfaced following a bullpen session Tuesday. The lefty continues to downplay the severity of the ailment, saying that he expects to return to mound work within a matter of days, but it still seems like something that could affect Ryu's availability for the start of Cactus League action.