San Francisco Giants reliever Luke Jackson (back) landed on the 15-day injured list on Sunday. After facing only one batter, the right-hander was removed from Saturday's meeting with the Diamondbacks because of lower back tightness. Jackson, who signed a two-year, $11.5 million this offseason, has appeared in just nine games this season. However, he's been decent during those appearances, sporting a 2.16 ERA with 10 strikeouts. But considering his history of injuries, fantasy managers may have ...