The 26-year-old returned following ankle surgery as he came on as a sub in Saturday's comfortable win over Newcastle and is now in contention to start in Tuesday's clash with struggling Cardiff City.
Wilshere ended a 10-year stay with Arsenal in the summer to join the 'Hammers' on a bosman free, having been told that he would not have an important role to play under Unai Emery.
Spekaing ahead of Tuesday night's game, Pellegrini hailed the England man, though he also admitted that the decision to bring him in was something of a risk.
"He was a high risk," he admitted. "We knew before he was not a player who would be available for every game, every week, but was a player of a quality that is not easy to bring to West Ham at a price we could afford.
"Maybe players of the quality of Wilshere at this moment can cost £100m, £90m, £70m. Good creative midfielders are very expensive.
"He wanted to play at West Ham, we took the risk and it has not been a good month for him but we have the second part of the season and I hope he will play most part of the games.
"It is never hard for good players to get into the team."