CINCINNATI – The Reds knocked back-to-back jacks off Javier Assad on Saturday night. But by then, the righty’s work in helping keep the Cubs’ injury-ravaged pitching staff afloat had already made him one of this team’s first-half lifesavers. “It’s been a time of need for us in the rotation. When you have injuries and you bring guys up to add to your rotation, he has more than delivered from that role,” manager Craig Counsell said before the game. “That’s been a really positive development in…