Bournemouth's pre-season has been rocked by news that striker Kroupi will be out for three to four months after undergoing surgery on a broken fifth metatarsal, with the club also confirming Eibenberger has joined Marco Rose's backroom staff as first-team coach.
Kroupi, 20, suffered the fracture during a training camp in Austria and flew back to England for the operation on Wednesday.
The timing is particularly cruel given the interest he had attracted this summer, with Barcelona, Bayern Munich, Tottenham and Manchester City all credited with admiration for the forward, though Bournemouth had maintained throughout that he was not for sale; the club has taken a similarly firm stance on winger Alex Scott, a target for Chelsea and Manchester United, as it looks to keep its squad competitive for Rose's first season in charge.
Kroupi took the Premier League by storm after joining from Lorient last year, scoring 13 goals to set the record for the most goals by a teenager in a debut Premier League season, surpassing the previous mark jointly held by Robbie Fowler and Robbie Keane.
Marcus Tavernier and Ben Gannon-Doak are expected to take on greater responsibility in attack during his absence, with Bournemouth opening their season away at Manchester City on 23 August.
Eibenberger's arrival reunites him with Rose, for whom he has worked before at Borussia Dortmund, Borussia Mönchengladbach and Red Bull Salzburg, most recently having been on the RB Leipzig staff the pair left together this summer. He joins assistant head coach Marco Kurth, assistant coach Frank Geideck, technical coach Fabian Friedrich and goalkeeping coach Frederic De Boever, who had already been confirmed as part of Rose's backroom team as he begins his first season at the Vitality Stadium following a three-year contract agreed in the spring.
Rose replaced Andoni Iraola, who left to take charge of Liverpool, and inherits a Bournemouth side that reached European competition for the first time in the club's history last season, adding fresh urgency to the appointment of a settled, experienced coaching staff around him before the campaign gets under way.