As Hertha Berlin's players returned to training four days ahead of schedule on Sunday, there was a notable absentee. "Ahead of the restart today, Salomon Kalou was excused from training, so that he can find a new club," tweeted the club's English language account, with little fanfare.

On some levels, it's not especially surprising news. One of the club's longest-serving players, Kalou is now 34 and was a fringe player under both Ante Covic, sacked after less than half a season, and his successor, Jürgen Klinsmann. But in the context of the winds of change blowing through the capital city club, it seems significant.

Kalou and Vedad Ibisevic were the two strikers who best represented the Pal Dardai era. The Hungarian coach plotted a safe course but steady as she goes no longer looks to be enough for the club who take their name from a boat. The €125-million (€142-million) investment from businessman Lars Windhorst's firm, Tennor Holding, gave him a 37.5-percent stake in the club just before the start of the season. A further investment has seen that rise to a shade under 50 percent, the maximum allowed under the 50+1 rule. Such a windfall brings a change in expectations.

Covic was unable to meet those and the call went out to former Germany and USA national team coach Klinsmann, who had recently joined the supervisory board at the behest of Windhorst.

Klinsmann has enjoyed a decent start to his reign, picking up eight points from five tricky matches but the World Cup winner is in the market for new blood. "We hope that no matter what we do, we will do something that makes the squad stronger," he said ahead of the club's departure to Florida for a mid-season training camp.

While the former Bayern Munich man remained tight-lipped about the mooted arrivals of Arsenal's Granit Xhaka, Paris Saint-Germain's Julian Draxler and Borussia Dortmund's Mario Götze, it's clear his ambitions for the club are high.

"The most important thing this year is getting away from the relegation area and being safe," Klinsmann said in a Facebook video chat with fans recently. "The following year we must attack a European berth, that is a clear aim. And then we can hopefully play for a title in three to five years and have a presence in Europe."

While Borussia Dortmund moved early to secure the signature of Erling Haaland, it's increasingly apparent that Hertha will be the Bundesliga's most active club in the January transfer window, traditionally a quiet time for Germany's top flight.

Ondrej Duda, who started last season in phenomenal form, now appears surplus to requirements while the club are also reportedly happy to let Alexander Esswein, Mathew Leckie, Peter Pekarik and several young players go, as they look to trim a bloated squad of 34 first teamers.

One of the qualities Klinsmann is expected to bring to the Hertha role is an ability to shake up a culture that has grown stale, something he was charged with doing in his time at the helm of the German national team. 

As well as the proposed clearout and early return to training, the 55-year-old coach has reportedly imposed stricter rules in an attempt to stiffen up the club's culture, something he also tried in his short stint coaching Bayern. One of the early alterations is in the fashion department, with Klinsmann insisting his players should not wear tracksuits while travelling with the club in attempt to increase professionalism.

No doubt the new man will be looking to drill his tactical and cultural approach in to his squad as Hertha head to their training camp in the USA, where Klinsmann has lived for several years, this week. 

He'll hope that by the time they return, one or two new faces might also need bringing up to speed. But speed is a quality very much of the essence. Hertha's next opponent after the winter break? Bayern Munich. Revolutions have to start somewhere.