The midfielder missed the opening day defeat at West Brom but played the final 30 minutes of the midweek Carabao Cup reverse against Bradford City.
Cantwell came through that unscathed and is likely to return to the starting XI against Birmingham on Saturday.
Rovers are also boosted by Carter’s return to training after a hamstring issue. The defender is still a few weeks away from being in contention but has made positive strides.
READ MORE: Blackburn Rovers transfer latest and situation they ‘wanted to avoid’
“Todd Cantwell is back. He made the game in midweek, went through the process this week and now ready for tomorrow,” Ismael revealed.
“Hayden Carter trained with the squad again, so that’s two days now. For sure too early for the game this weekend because he was missing the pre-season.
“He needs a few more weeks, but at least he’s back with the squad. Otherwise, the two other guys with Adam Forshaw and Jake Garrett, it’s obvious that they’re still injured.”
“He can be a technical leader on the pitch. He’s got all the potential to do that,” he added on Cantwell.
“Now it’s all about his fitness and to stay healthy. I think he made a great pre-season. He just got a little setback last week, but now he’s back.
“Hopefully, he can stay healthy and touch wood, it might be a big season for him. He’s very motivated to do that.”
With Lewis Travis unlikely to be involved, Sidnei Tavares could make his first league start. After an ankle injury in pre-season, he is ready to stand-in for the captain if called upon
Ismael was encouraged by his first showing in midweek but, equally, stressed the need for patience with the new arrivals.
“It was encouraging, we know what we signed as a player,” Ismael said.
“I’ve got the final product in my mind. How it looks like with these players. We know how we train, but Sidney is the same, it will take time.
“He got injured on day one in the pre-season, he missed four weeks. He just came back at the very end.
“He needs time as well to find his rhythm. He needs game rhythm. This is what we expected from him.
“Hopefully, he can stay healthy. Now, it’s only the consistency that will help the player to reach his full potential.”
Birmingham have made a fast start to the season after their promotion from League One. An impressive opening day draw with Ipswich Town was followed up by beating Sheffield United.
“They have what everyone wants, they’re on an upwards charge,” Ismael said.
“At some point, everyone will have momentum. It’s about the timing of that.
“It’s a team that got promoted with a big ambition. We saw clearly on the transfer market but we’re playing at home. We know that every game is tough.
“You have to earn your points. We are ready for the game and to make sure that we can get the three points I think that we know exactly what we have to do.
“They have just got promoted but, in reality, they’ve got a strong squad. They spend a lot of money on the market, clearly. It’s a great game for us and we are prepared.”