Zubi said no.
According to a report from Mundo Deportivo, the 28-year-old was offered by his agents to three La Liga teams: Valencia, Real Madrid, and Barça. All three said no, immediately. Guarín had his foot out of the door at the nerazzurri, but he's going to stay at least until January, when the window opens again.
It's worth noting that Barça has shown interest in Guarín in the past, while the Colombia international was still at FC Porto, but the Blaugrana later decided not to move on with the talks, and Fredy went to Italy.
The report from MD says that Barça never thought about Guarín this summer, and made the signing of Ivan Rakitic the priority at midfield. This time, it was the player's agent that wanted him moving to Camp Nou, but the Catalans decided to stick with their roster, since Luis Enrique's plan is to use Barça B players as much as possible, and not rely on outside players.
In both cases, of Guarín and Kovacic, no deal was made, and Barça cannot buy anyone else now, since FIFA has banned the club from doing transfers for the next couple of windows.