Ben Brereton is doubtful for Rovers’ return to action this weekend.

Brereton was replaced early in the second half of Chile’s friendly win over Paraguay on Tuesday.

He then faced a long-flight back from Santiago, and having been assessed by the club’s medical staff, Jon Dahl Tomasson says the top scorer is doubtful for the trip to St Andrew’s.

It would serve as a big blow for Rovers, with Brereton having scored in each of the three games leading into the international break.

He had spent five games out of the starting line-up, a combination of a hamstring concern last month, as well as suspension for the FA Cup tie at Leicester City.

But he took his tally to 14 for the season with goals against Stoke City, Reading and Sheffield United.

“Ben went off on 51 minutes and had a long flight back, it's a long journey which is not the best,” Tomasson said.

“It’s doubtful if he’s going to be able to play against Birmingham.

“He is one I would like to have, he scored three goals in the last three games before the break and especially at this stage of the season you would like to have him on the pitch, but he’s doubtful."

Tomasson said that while there is no serious injury, Rovers will be mindful of the attacker's fitness.

“It’s a long distance on the plane from Chile,” the head coach added.

“He’s not injured, injured, in that way and with the time difference.

“He went after the game after 51 minutes so it’s a risk.

“I’ve had conversations with the medical team and Ben but of course he’s doubtful.”

Tomasson has confirmed that Bradley Dack has returned to training during the month having been out since limping off with a hamstring injury in the win over Swansea City on February 15.

The head coach is yet to decide whether the 29-year-old will return to the matchday squad, or to leave him behind to be involved in an behind-closed-doors game on Sunday.

“Bradley has been back on the pitch. He played 30 minutes in an internal game as the rest of the players did,” Tomasson added.

“He is missing match fitness, you can see that, but he's getting better.

“I don’t know, I need to decide that (if he will be involved) tomorrow.

“I will speak with Bradley about that and we will decide that.”

Rovers had six players away on international duty during the break, with Brereton playing just once for Chile in a friendly with Paraguay.

Thomas Kaminski (Belgium) and Dom Hyam (Scotland) didn’t play any minutes in the break, while Sorba Thomas played 35 minutes for Wales.

Ash Phillips started all three games for England Under-19s in the break, with Adam Wharton featuring in all three, starting once.

Although being a club manager, Tomasson has been involved with the Denmark national team as a coach, so can see both perspectives when it comes to the break.

“I worked with the Danish federation so I know how important it is to have a good communication and working well together with the club,” Tomasson added.

“National teams are borrowing the players and on the other hand it’s a great opportunity for the players, a time to make them proud, and should also make Rovers proud with all those players in the national team duties because it says a little bit about the journey.

“Some teams are training less, some are training more, some players are playing, such as Ash Phillips who played three times in a week.

“Then you have Dom who hasn’t played one minute, but was called up later.

“We try and monitor everything they’re doing.

“The worst thing you can have is a player gets called up and he’s only laying in bed for a week, sometimes that happens, but our players are alright.”