It apparently wasn't the flu or some bad sushi that sent Chris Sale to the hospital during the AL Championship Series against the Astros.

No, the reason was far different than most would have expected: an infection due to a belly-button ring.

Astros star second baseman Jose Altuve underwent surgery Friday on his injured right knee, according to MLB.com.

Altuve is expected to be ready for spring training next year.

Indications are that Red Sox ace Chris Sale will not pitch in Thursday's Game 5 of the American League Championship Series because he is still weak from the stomach ailment that sent him to a hospital on Sunday night, according to a report by ESPN's Buster Olney.

The earliest Sale is likely to come back is Game 6 in Boston, per Olney's report.

Earlier today, SS Didi Gregorius underwent “Tommy John” surgery on his right elbow. The surgery, which went as expected, was performed by Dr. David Altchek at the Hospital for Special Surgery in Manhattan.

The Milwaukee Brewers have added RHP Zach Davies to the National League Championship Series roster, replacing LHP Gio Gonzalez, who left Tuesday night's game with a high left ankle sprain.

The move means that if the Brewers make it to the World Series, Gonzalez cannot be on the roster, as a player replaced due to injury in one playoff series is required to sit out the next one.

Brewers starter Gio Gonzalez was forced to leave his start in Game 4 of the National League Championship Series after only one inning because of a high ankle sprain.

Red Sox starter Chris Sale was admitted to a local hospital Sunday afternoon because of a stomach illness, the team said.

"He's at the hospital. From what I know, it is nothing serious," manager Alex Cora said. "Whenever you have to go to hospital, you have to be quote-unquote 'worried.' But he should be fine."

Yankees shortstop Didi Gregorius will undergo Tommy John surgery and miss part of the 2019 season, the team announced Friday.

"We're optimistic that he'll be back at some point during the season," Yankees manager Aaron Boone said. "I don't want to speculate too much on when."

But Boone added it's "realistic [Gregorius] plays the bulk of the season with us."

While he is expected to be in the lineup for Game 1 of the ALCS, Carlos Correa remains bothered by a back injury that sidelined him earlier this season.

Correa says he's still in pain and every swing and miss hurts his back. On some days, walking is uncomfortable.

He hit .239/.323/.405 with 15 home runs in 402 regular-season at-bats. He went on the disabled list in late June with a sore back and missed a month and a half.

What began as a disastrous night for the New York Yankees got worse in the fourth inning of Friday's 5-4 loss to the Boston Red Sox in the American League Division Series when center fielder Aaron Hicks was removed with right hamstring tightness.

Hicks will undergo an MRI on Saturday to determine the severity of the injury and whether it might require him to miss time.