Texas Gov. Rick Perry (Jim Young/Reuters)

A top strategist for Rick Perry said that the Texas governor's back pain was a major factor in the former presidential candidate's campaign struggles. 

"I think it had a big impact," Dave Carney, a longtime strategist for Perry, said at the Harvard Institute of Politics' "Campaign Managers Conference" last week. Audio of the event was released Monday.  

Perry underwent back surgery in July 2011; Carney said that the governor was told it would only take two weeks to recover. Instead, it took four months. The governor announced his campaign in August to great fanfare, but ended his campaign in January after a series of lackluster debate performances. 

"The whole campaign was built on a very aggressive, arduous schedule of travel in order to make up for lost time," Carney explained. The pain made it hard for the governor to sleep, "more difficult to study, more difficult to be comfortable." However, he said painkillers did not play into Perry's debate missteps, as some have speculated.

"It's just a fact, it's not an excuse," the strategist added. "We passed tort reform in Texas, so we can't actually sue the doctors for what they told him."