According to the source, Arsenal could be willing to listen to offers for the young defender, so it is quite possible that he could be on his way out.
On the other hand, Liverpool’s weakest position is currently left-back, with only the less than impressive Alberto Moreno playing in that position. Young Joe Gomez can fill that place if needed, but the Reds are still going to need some natural left-back.
Gibbs is tied to the Gunners until 2018, but there are no indications that Arsenal is going to get in talks with him about his contract being extended.
With all this being said, and Gibbs starting only three games in the Premier League last season for the Gunners, it seems like his transfer to Liverpool has a really great chance of happening.