Vargas was placed on the 15-day DL Friday with a left flexor strain, the Kansas City Star's Andy McCullough reports. The move is retroactive to May 6, but a flexor strain is often a precursor to Tommy John surgery, so he should be considered out indefinitely. Chris Young will take his spot in the rotation, but assuming Vargas misses significant time, the Royals may look to add another starting pitcher, either from the farm or in a trade.