Williams Martinez scored West Bromwich Albion's final goal of the Premiership campaign but that was not enough to secure him a permanent move to The Hawthorns.
The centre-back scored during Albion's 2-2 draw at Everton on Sunday but will return to his employers, Defensor, having not convinced Bryan Robson, the Albion manager, that he is worth a permanent deal.
Jan Kozak, the Slovakia international midfield player, will return to Artmedia Bratislava for the same reason.
Both joined the club during the January transfer window but now, as Robson contemplates life in the Coca-Cola Championship, the rebuilding process begins.
"They will be going back to their clubs," Robson said. "I've obviously had a chance to have a look at them and I just feel we need that little bit better quality, if we can get it, in the summer but they're both cracking lads and I'd like to wish them all the best in their future careers."
Kozak made four successive starts for the Baggies in March but failed to figure in the line-up again after the defeat by Tottenham Hotspur at White Hart Lane. He also made two substitute appearances in February.
Martinez made his full debut against Everton and had a mixed time. His goal was impressive enough but he was harshly adjudged to have fouled Mikel Arteta inside the penalty area, enabling Everton to equalise. Martinez's only other appearance was as a half-time substitute in the 6-1 defeat at Fulham in February.