Former UFC bantamweight champion Holly Holm underwent thumb surgery on her left hand this week, according to her manager, Lenny Fresquez.

Holm suffered a "shattered thumb" during her five-round unanimous-decision loss to Valentina Shevchenko on July 23. A former world boxing champion as well, Holm has been instructed not to use her left hand for six weeks.

Holm believes the injury occurred in the first or fourth round. Fresquez made it clear the camp does not blame the loss to Shevchenko on the thumb injury.

"She had eight pins inserted into her hand," Fresquez told ESPN.com. "We'd still like to fight by the end of the year. As far as an opponent, we'll have to see who comes up. Whoever she fights, Holly needs to take care of business."

Holly Holm needed surgery to repair a "shattered" left thumb suffered in her loss to Valentina Shevchenko. Nam Y. Huh/AP

A native of Albuquerque, New Mexico, Holm (10-2) was on the top of the MMA world as recently as November, when she knocked out Ronda Rousey via head kick to win the UFC championship.

Holm has been in a bit of a tailspin since. She surrendered the title to Miesha Tate in her first attempted defense at UFC 196 in March.

The loss to Shevchenko marked the first time in her combat sports career she has lost back-to-back fights.

Holm is no stranger to fighting through injury in a fight. In April 2014, Holm suffered a broken left arm during a five-round TKO win against Juliana Werner. That fight took place for Legacy Fighting Championships.

Before the Shevchenko fight, sources close to Holm said she was interested in fighting at UFC 205 on Nov. 12 at Madison Square Garden because of the venue's rich boxing history.