Padres place Richard on DL, activate Ross

The San Diego Padres placed pitcher Clayton Richard on the 15-day disabled list on Sunday, while activating Tyson Ross from the 15-day DL.

Richard is suffering from an intestinal virus. He last pitched in Saturday's 8-1 loss against the Diamondbacks, allowing seven runs -- five earned -- on seven hits and four walks over 3 2/3 innings.

In six starts this season, Richard is 0-4 with an 8.54 ERA and has walked 17 batters in just 26 1/3 innings.

Ross was placed on the disabled list on April 18 with a left shoulder subluxation. Acquired in a trade from the Oakland Athletics this offseason, the right-hander is 0-1 with a 3.86 ERA and 12 strikeouts in three starts.

The 26-year-old will be available to pitch in relief for Sunday's game against the Diamondbacks.