Revealed: Why Sheffield United can sign overseas duo

The duo, recruited on loan from Bayer Leverkusen and Changchun Yatai respectively, arrived at Bramall Lane on transfer deadline day; 24 hours after Sander Berge became the most expensive player in United’s history after leaving Genk.

Speaking earlier this month, United manager Chris Wilder revealed clauses had already been inserted into the Retsos and Zivkovic deals giving United the right to keep them should they so wish.

Shedding further light on those agreements, Bettis said: “Even with the loans, we’re moving forward with the way we’re doing deals, with both of them having options to turn them permanent in the summer.

“It gives us that freedom and it’s our decision solely come the summer.”

After unveiling Jack Rodwell and Jack Robinson at the beginning of the window, the swoops for Berge, Retsos and Zivkovic represented Wilder’s first serious foray into the overseas market since being appointed in May 2016.

Languishing in League One at the time, United flew out to Dubai for their winter-break ranked fifth in the Premier League, after beating AFC Bournemouth on Sunday.

Bettis comments confirm United’s hierarchy has also changed how they draft transfer agreements in recent years; learning from the type of past mistake which enabled Dean Hammond, who failed to impress after being recruited by Wilder’s predecessor Nigel Adkins, to extend his own contract despite being declared surplus to requirements by the 52-year-old. United were later forced to reach a settlement with the former Brighton and Hove Albion midfielder.

Retsos, aged 21, is a Greece international while centre-forward Zivkovic, two years the defender’s senior, has represented the Netherlands at under-21 level.

“January is always a difficult market, with people trying to buy their way out of problems or injuries and you (can) end up overpaying,” Bettis said. “We were in a good position where we were doing well in the league and our injury record has been good as well.”

“We didn’t have that pressure,” Bettis added. “So it was all about making the right decisions and if we didn’t find that opportunity, the money would just roll forward until the summer.”