Asif, 33, and Butt, 31, were banned along with Mohammad Amir after spot-fixing incidents during a Test against England at Lord's in August 2010.
Amir, 24, is back in the Test team but Asif and Butt are yet to be recalled.
"We are waiting for them to prove their case," said Pakistan Cricket Board chairman Shahryar Khan.
"They'll have to knock the door down before they are considered."
All three men were jailed for their parts in the incident, which saw Amir and Asif deliberately bowl no-balls as part of a betting scam.
Khan added: "Amir, from day one, has admitted his faults and apologised.
"The other two didn't admit from day one, only once they were sentenced by the court did they admit. There is a difference there."
Amir was given a muted reception at Lord's on Friday as he bowled for the first time in a Test since being banned.

In particular, we wanted to find out what you really feel about selfies.
So, for Safer Internet Day 2017, we spoke to a big group of 10 to 12-year-olds to see what they thought.
How many post like to post them? How many do they take before they get the perfect snap? Do they edit their pictures before putting them online?
See if you can guess what they said about social media with our quiz, and then read on to find out more about what they said.
While many websites say you shouldn't have a social media account until you are 13, we found out last year that many 10 to 12-year-olds have at least one account.
This year, the first thing they told us was that they enjoy to use it.
More than 4 in 5 said they feel happy, sociable or excited when on social media.
Many also told us they'd feel left out if they didn't have it.
A selfie is when you take a picture of yourself on a smartphone or camera
People use social media for lots of different reasons: talking with friends, sharing funny videos or posting photographs.
We wanted to know how many 10 to 12-year-olds use social media to post selfies.
Our survey revealed that many do, with more than half of everyone saying they use social media to share pictures that they've taken of themselves.
Posting selfies is also slightly more popular with girls than boys.
Of course, even if you take a selfie, not everyone posts them on social media.
But the ones that do like to do it told us it's not as simple as taking one quick photo and sharing it.
More than 4 in 5 said that if they take a picture of themselves to put on social media, it was "important" to look good.
And it can be hard to take the right photo first time.
On average, the 10 to 12-year-olds who put pictures of themselves on social media said they take about four pictures before getting the perfect snap. But about one in six take six or more pictures before they're happy with the result.
Even when they get the right picture, some still aren't happy to publish it online.
The majority said that, at least sometimes, they edit the picture too, by putting filters, effects or stickers onto it, a bit like in the picture above.
The results suggest that, for many, there is pressure to look a certain way in selfies.
One in five told us that when they look at photos of celebrities on social media, it makes them worry about how they look.
It wasn't just the group's own selfies which Newsround asked about.
Many people like to look at selfies posted by their mates too.
Half of the 10 to 12-year-olds we spoke to said looking at selfies posted by their friends makes them feel happy.
Survey conducted online by ComRes of 1,001 10 to 12-year olds in the UK between 4 and 11 January 2017
While there are always different opinions, it's clear that, to many of you, selfies - either your own or your friends' - are an important part of being on social media.
But what do you think about pictures of you that your parents share on social media? Click here to see what Newsround found out...
Mohammad Asif and Salman Butt have been told they must "knock the door down" before they are considered for a return to the Pakistan team.
[NEXT_CONCEPT]
You've been telling us exactly what you think about social media.