Injury-hit Heart of Midlothian have been forced to call up 19-year-olds Matthew Gillies and Gus Stevenson from their loans with Stenhousemuir to pad out their squad to face Thun in the Conference League on Thursday.

Head coach Wouter Vrancken has travelled with a squad of only 19 players - six short of the maximum and including three goalkeepers - for the match in Switzerland.

It came after key winger Calvin Miller was ruled out for two months with a knee injury in Sunday's Premier Sports Cup semi-final defeat by Hibernian.

Midfielder Tomas Magnusson has also been sidelined until after the international break with concussion suffered at Hampden.

With 10 first-team players now sidelined, Vrancken admitted he will be forced to play some players out of position against the Swiss champions.

"It's a puzzle," he said. "I'm always happy to see that the players we work with and play out of position, or talk with, are always directly motivated to do it.

"They know how much they help the team by doing it. It's good to see because they take responsibility and they don't live by excuses.

"That's how they did it already for weeks. That's how we also get good results and good performances.

"Now we have to try to do it two more times before the international break."

Miller had played in a number 10 role on Sunday, setting up the opening goal for Claudio Braga, while fellow winger Rogers Mato has been utilised at left-back.

"It's not pleasant to lose players, especially important players," Vrancken admitted. "The last two games, especially the Rangers game, Tomas and Calvin were both the best players on the pitch.

"Losing them in the first half on Sunday and killing the game by this is not a nice thing to experience.

"We have travelled with 16 outfield players here, including Matthew Gillies and Gus Stevenson. So two goalies on the bench and six outfield players."

Gillies and Stevenson joined Stenhousemuir this summer on Scotland's new co-operation agreement loans that allow players to be recalled mid-transfer window to play for their parent club.

Centre-half Gillies has started 10 times and been a substitute on five more occasions, while attacking midfielder Stevenson has started seven times and come off the bench in six more as they helped Stenhousemuir into an early surprise lead in Scotland's second tier.

Hearts and Thun are both seeking their first Conference League wins this season.

Thursday's hosts are also a disappointing ninth in the Swiss Super League but ended a run of five games without a win by coming from 4-1 behind to beat bottom side Lausanne-Sport 5-4 on Sunday.

"When you have a victory like this, it's always an incredible win and it gives a boost," added Vrancken.

"They have a good team, they have a lot of energy, they have a lot of intensity. They have direct play, going fast forward a lot of moments. Good quality players also in front.

"We have to be spot-on, we have to be on our level. The aim is to try to get a win here."

Thun head coach Gian-Luca Privitelli says Hearts' absences do not change his gameplan.

"We think the two wingers and the strikers are good players," he told the Edinburgh Evening News. "In midfield, they use the ball well.

"There are four or five players we studied a bit more, but it's about the whole team and the style. It's going to be a very tough game.

"I have the impression that our opponents are a very good, modern-style team with very good moves. They play a good, pressing game and they are very intense in the duels."

Midfielder Fabio Saiz and defenders Genis Montolio and Mats Seiler miss out for Thun through injury, while a third centre-half, Louis Passavant, is an injury doubt after sitting out Sunday's stunning comeback win over Lausanne-Sport.

Privitelli has been rotating his squad and made five changes between their 3-2 defeat by Lugano and Sunday's victory.

However, Sunday's line-up only showed two changes from the side that lost 1-0 at home to Hajduk Split in their last Conference League outing.

Midfielder Tom Strannegard was also missing from Sunday's squad, but Estonia midfielder Mattias Kait, who had a spell on loan to Ross County from Fulham, was one of those who returned to the starting line-up against Lausanne.

Miller and Magnusson have been added to Hearts' lengthy list of absences, with Gillies and Stevenson stepping in from their loans to Stenhousemuir.

The two 19-year-olds played in Friday's 3-0 home defeat by Livingston but missed Tuesday's 4-1 Challenge Cup win over Berwick Rangers.