Goal!

Santiago MuÃ±ez (Kuno Becker) is a skilled footballer. The son of a gardener who lives in a barrio section of Los Angeles, Santiago works as a busboy in a Chinese restaurant and helps with his father's (Tony Plana) gardening business. His ultimate dream is to play football professionally. Due to his poverty and the fact that he plays solely for a club made up of Hispanics from a local car wash, he feels his chances are slim. Santiago is noticed by Glen Foy (Stephen Dillane), a former Newcastle United player who works as a car mechanic but still has ties to his old team. Glen arranges to get Santiago a tryout with Newcastle United, who recently signed talented new player Gavin Harris (Alessandro Nivola). Needing to get to England, Santiago begins to save his money in an old shoe, but his father finds the stash and takes it to buy a GMC truck to allow them to work for themselves, believing that Santiago's dreams are hopeless. His dream is not lost though, as his grandmother (Miriam Colon) sells off her jewellery to buy him a ticket to England.
Glen warmly welcomes Santiago to his home and takes him to the tryout. Unfamiliar with the English style, he performs poorly. Glen convinces the team's manager that Santiago needs a month's trial to show his full potential. Santiago does not tell club nurse, Roz Harmison (Anna Friel), that he has asthma. After a month, a jealous teammate crushes Santiago's inhaler before a reserve game. An asthma flare-up prevents him from being able to run hard, and his coach lets him go. While on his way to the airport Santiago meets Gavin Harris, who was late to arrive to the team. Harris finds out what has happened and makes Santiago explain it to the manager. The manager allows Santiago to stay, provided he gets treatment for the asthma. Santiago earns a contract for the reserves team and moves in with Gavin. Finally he gets onto the first team as a substitute in a match against Fulham. There he wins a penalty for Newcastle, which is taken by Gavin winning them the match. Unknown to anyone else in his family, his father watches the match on TV in the USA, and after finally watching his son play, he leaves a proud father. Despite the victory, the manager informs Santiago that his weakness is that he does not pass the ball off. That night, he and Gavin go out partying. A picture of the two winds up in the tabloid The Sun, causing anger from the manager. At the same time, Santiago's friend, Jamie, suffers a career-ending injury that only causes him additional grief.
Meanwhile, back in Los Angeles, Santiago's father dies of a heart attack. Devastated, Santiago plans to return home. While in the airport waiting for his flight back to Los Angeles, he decides not to return and reports back to training. Believing he may not make it to the playing eleven, he goes to St James' Park and practices till late in the evening, and is informed by the manager that he has been selected to play against Liverpool F.C.. On match day, Gavin puts Newcastle into the lead. Before half-time, Liverpool makes a comeback with two goals, from Igor BiÅ¡Äan and Milan BaroÅ¡. In the final minutes of injury time, Santiago assists Gavin in scoring the equaliser by finally passing the ball to him, to make it 2â2. However, a draw will not be enough to earn Newcastle a place in next season's UEFA Champions League. Mere minutes before the end of the game, Gavin is tripped and Newcastle gain a wide free kick, which Gavin gives to Santiago. Santiago, with the hopes and prayers of the whole city of Newcastle resting on his shoulders, scores, and Newcastle win 3â2. Glen reveals to Santiago that his grandmother is trying to call. She mentions that his father did watch his first match against Fulham, after learning this from a fellow supporter (a cameo by Brian Johnson, lead singer from AC/DC, who was born and raised in Newcastle). Santiago shouted to Glen that his father saw him play and was proud of him before he died. Glen replies: "He's probably watching you right now." The film happily ends with Santiago shedding tears of joy while embracing his dream.

Question: How long does Glen think it will take for Santiago to show his full potential?
Answer: a month