Despite facing left-handed starters Saturday and Sunday, designated hitter Billy Butler was not in the lineup for the Athletics. Manager Bob Melvin said Butler was out sick due to nausea and vomiting, though he ruled out the flu.

There seems to be more to this story than a simple illness, however. According to Susan Slusser of the San Francisco Chronicle, Butler was injured in an altercation with teammate Danny Valencia on Friday. No one with the A's has commented on the incident. From Slusser:

"No comment," Valencia said after the team's 4-2 loss to the White Sox. "What happens in the clubhouse stays in the clubhouse."

Fair or not, Valencia has a reputation for being a clubhouse liability because he's changed teams so often in his career. The A's are his sixth team since 2012. That's why there was little interest in him at the trade deadline despite a .302/.351/.478 batting line and 15 home runs.

Both Valencia and Butler have had their playing time reduced this season. Butler has been a platoon DH against lefties most of the year while Valencia only recently started losing playing time to Ryon Healy. The A's want to get a look at young players down the stretch, including Healy, so veterans are sitting.

Danny Valencia (l.) and Billy Butler were reportedly involved in a clubhouse altercation. USATSI

The exact nature of the altercation is unknown, so it's unclear if this is something serious that needs to be addressed, or just a matter of "boys will be boys." Nausea and vomiting are common symptoms of a concussion, and if the altercation was serious enough to cause a concussion, that's a big problem.

Not all teammates get along. Stick 25 alpha males in a room together for seven months a year and disagreements will happen. That's life. Physical altercations are another matter. If this one caused Butler to miss time with an injury, it's something the A's shouldn't take lightly.