Jeremy Hefner will undergo Tommy John surgery after a second opinion on the partially torn MCL in his pitching arm confirmed surgery was needed, according to a source.

Hefner visited Dr. James Andrews on Monday. Hefner previously had Tommy John surgery recommended to him by New York Mets doctors.

He admitted he hadn't been as honest with the Mets about the pain in his elbow because he wanted to stay in the rotation.

The 27-year-old entered the All-Star break with MLB's best ERA dating back to June 4, but went 0-2 with a 9.13 ERA in his five starts after the break.