Source: Red Sox's Eovaldi to have elbow surgery

How serious is Eovaldi's elbow injury? (0:52)

Stephania Bell breaks down the severity of Nathan Eovaldi's elbow surgery, which will have him out four to six weeks. (0:52)

Boston Red Sox starting pitcher Nathan Eovaldi will have elbow surgery on Thursday and will be out of action for 4-6 weeks, a source confirmed to ESPN.

The Athletic first reported that Eovaldi would have surgery.

The Red Sox placed Eovaldi on the injured list Saturday because of a loose body in his right (throwing) elbow. Red Sox president Dave Dombrowski said then there was a chance the loose body, described as cartilage, was there when Eovaldi underwent surgery while with the Tampa Bay Rays in March 2018 and missed two months.

Eovaldi said he didn't experience any symptoms after his start against the New York Yankees last Wednesday, when he tossed six innings while allowing one unearned run, walking one and striking out six.

The 29-year-old knew something was wrong when he could not straighten out his arm during the team's off day in Tampa Bay.

Eovaldi signed a four-year, $68 million deal in December. He is 3-3 with a 4.08 ERA in parts of two season in Boston. So far this year, the hard-throwing righty has a 6.00 ERA in four starts, allowing 14 runs in 21 innings pitched, striking out 16 and walking 11.