The 24-year-old has been struggling to secure regular first-team action at the Santiago Bernabeu, making just 11 starts in La Liga this campaign.
He recently acknowledged he might have to leave Madrid to get more playing time and Alba has stressed there would always be room for his former Valencia team-mate at Camp Nou.
"Good players are always welcome," Alba told reporters when asked about a potential move for Isco. "I have a lot of time for Isco. I still know him from when we played together at Valencia and I know he has a lot of quality.
"Time will tell whether anything will happen..."
Isco has a contract with Madrid until June 2018, meaning the Champions League holders could opt to cash in on the attacking midfielder come the end of the season if he does not agree to an extension, in order to prevent him from leaving on a free next year.