"Reduced to rubble": TV pundit lambasts Eintracht Frankfurt's Albert Riera

Eintracht is "in ruins", Hamann told Sky. "It's not just the results, but also what you hear from the players." Hamann raised concerns about the development of certain players under Riera, without going into specifics: "What's happened to Götze or Uzun... it's simply not possible to achieve something like that in such a short space of time."

Götze started the first four matches under Riera, but then found himself on the sidelines for nine of the next ten games: he sat out 90 minutes on the bench six times, was left out of the squad once, and logged only 56 minutes across two substitute appearances.

Uzun was sidelined through injury when Riera arrived and was brought back into the team very gradually after his recovery. In the last three matches, the 20-year-old has started for the Hessians in each game, scoring two goals and providing one assist.

Hamann expects another managerial change at the end of the season, as he believes Frankfurt are heading in the wrong direction. "When you bring in a new manager, you want to see progress. The first few games were okay, but since then things have gone backwards," said the 52-year-old. "They'll probably get a new manager again in the summer – and then we'll have to see how things pan out."

Riera briefly appeared to steady Eintracht Frankfurt after Dino Toppmöller's February dismissal. The side looked more solid at the back, winning three of the Spaniard's first six games in charge and losing only once, in Munich.

Yet their 1-0 win over bottom-of-the-table 1. FC Heidenheim two months ago remains their last triumph; since then they have looked toothless in attack and vulnerable at the back, risking a European place.

After Friday's loss at BVB, sporting director Markus Krösche sidestepped questions about the manager's future. "We are disappointed by the defeat and will do everything we can to beat Stuttgart next week," said the 45-year-old.

Beyond the poor results, Riera has also damaged his standing internally with outspoken comments; his pre-match media criticism before the HSV game drew flak, and the subsequent 1-2 home loss to the promoted side only hastened the slide.

Bild claims the split is already done deal, a view shared by Sky.

Only Bundesliga matches are included. When Riera took charge, Eintracht had already been eliminated from the Champions League and the DFB-Pokal.