McCoist confirmed reports he had been watching the 29-year-old, who has scored 37 goals in 60 games for his club during the past two seasons, but he was coy over the likelihood of a January move for the player.
McCoist told the club's Blues News: "I don't like discussing other team's players but he's very good. We've been watching a lot of games.
"Valladolid are going well in the second tier in Spanish football just now and he has been battering in all sorts of goals.
"He is someone else's player and it wouldn't be fair of me to say much more than that, but he is a top player."
Asked if he would be interested in signing the forward if he became available, McCoist said: "Quite possibly. He is a very good player and, if the opportunity arose, yes."
McCoist is keen to sign a striker after losing Kyle Lafferty to injury until the end of February, which followed a long-term injury to Steven Naismith.
Top goalscorer Nikica Jelavic's future has also been the subject of constant speculation.