Complex sentence: Thome experienced stiffness in his lower back in a game against the Chicago Cubs on April 28, and early in May, he was placed on the 15-day disabled list with a strained lower back.
Split into simpler sentences: Thome experienced stiffness in his lower back in a game against the Chicago Cubs on April 28. In May, he was placed on the 15-day disabled list with a strained lower back.