The Argentinian has scored three goals already this season and that is already more than in his previous three and a half years in England with Chelsea and Blackburn. Di Santo's role in the team has become more prominent with Hugo Rodallega sidelined by a knee injury but Martinez said the 22-year-old's worth to the side is not just measured in goals. "Franco keeps progressing. Early in the season when he didn't score his overall play was outstanding," he said. "You don't see many strikers who are powerful, strong, can run all day, have a fantastic first touch, are good in the air and a clinical finisher. "He is a great prospect but is still only 22, still progressing. "He is at a very good moment in goalscoring terms but his overall contribution to the team has been very good. "We need to allow him to carry on enjoying his football and if we do that it will be a big season for him and Wigan."