Celtic's pursuit of centre-back Zinedin Smajlovic hit a snag after Sandefjord rejected bids from both the Scottish champions and Olympiacos. The Norwegian club wants closer to £4.3m for the 22-year-old defender, despite offers of £3.5m. This represents a significant investment target for Brendan Rodgers' side as they look to strengthen their backline ahead of European competition.

Meanwhile, Celtic are intensifying discussions with Boca Juniors over left-back Marcelo Saracchi. The 28-year-old discovered he's not part of head coach Rodolfo Arruabarrena's plans following his loan spell at Parkhead, making a permanent return increasingly likely. His versatility and experience could prove vital for Celtic's domestic and European campaigns next season.

In other transfer news, reported Celtic target Soufiane El-Faouzi appears set to sign a new deal with Schalke running until 2030, with nearly £1m annual salary. Go Ahead Eagles have also confirmed they won't block Jakob Breum's potential exit, despite Celtic's unsuccessful January bid for the £4m-rated attacking midfielder.

Celtic will resume pre-season training this Friday with approximately 21 players reporting back, though several World Cup participants remain absent. The transfer activity suggests serious preparation for the challenges ahead.