Keegan said: "Jose is improving with every game. You have got to remember, he has to learn the language - we have got a back four where only Steven Taylor speaks English.
"It has taken him a little while to adapt. We have had a couple of meetings with his brother about what he has to do to improve.
"His brother speaks good English, and when Jose was out of the team, he was more or less asking, 'What does he need to do to get back into the team?'.
"Whatever you are seeing now, it will be another 50% once he has got a pre-season with us under his belt and has not been interrupted like he was last year.
"Apparently, he did not have a full pre-season, and that is vitally important for players.
"Players who miss any part of pre-season usually suffer somewhere in a season, and Jose, like all of them, had probably had a little problem with that."