The Tech3 GasGas rider suffered a horrible crash in FP2 for the season-opening Portuguese GP, sustaining multiple back and jaw fractures after hitting an unprotected tyre barrier.
Espargaro has been out of action since then, only riding his MotoGP bike prior to Friday at Silverstone slowly up the hill at the Goodwood Festival of Speed last month.
Returning to full-time action on Friday at Silverstone, Espargaro ended Friday 21st of 22 riders having found almost three seconds in lap time from FP1 to FP2.
Asked by Autosport if he found Friday more mentally challenging or physically demanding, Espargaro responded: “This morning, the mental side [was tougher], I was destroyed.
“I never slept between sessions [before] and I had to take a one hour nap between the sessions because I was overloaded.
“The brain was finished. Then this afternoon, I was with more natural actions, physically I couldn’t make the change of direction enough.
“Luckily the bike is a rocket, even doing the change of direction onto the back straight quite slowly, I was one of the fastest on top speed, which is unbelievable.”
Espargaro also commented that making his return at such a high-speed track made for a “very, very stressful” experience.
“It was one of the most stressful days of my career, in this place where it’s a fast track, changing direction with this kind of speed, my brain was not as fast as everything was coming,” he said.
Source: Autosport