Nadal pulled out of the Australian Open last month at the quarter-final stage.
The Spaniard has strained the top of his thigh, although it is not expected to keep him out for too long.
But Lisanti has warned Nadal that if the problem is not treated right, he could face a similar problem to Andy Murray.
Murray is set to miss a number of months after undergoing hip surgery in early January.
“Most of the injuries (at the Australian Open), apart from Sloane Stephens, were lingering injuries from 2017,” Lisanti said on The Tennis.com Podcast.
“First, Rafael Nadal, his injury. He had to retire which never happens, he never quits.
“So we think it’s his Iliopsoas muscle, so sort of the muscle that comes all the way from your back to the front of your thigh that kind of helps you move that leg and hip flexion and all this stuff, so very important.
“My concern is that a small muscle tweak, minor injury as they say, is something that could, if he’s not treating it right and not taking the time to heal, that could extend into an injury like Andy Murray has which is a little bit more serious and he’s out for a long time.”
Nadal could lose his world No 1 spot this week to old rival Roger Federer.
Federer will topple Nadal if he reaches the semi-final of the Rotterdam Open.
Federer beat Ruben Bemelmans yesterday and faces Philipp Kohlschreiber in the last 16 at 6.30pm today.