When it comes to Celtic and Rangers handing new signings just ONE opportunity to make the grade at first-team level, only to never feature again - there has been plenty of cases over the years.
Just last week Rangers allowed Polish defender Mateusz Zukowski to depart for Slask Wroclaw. The right-back was signed for decent money to provide fierce competition for Ibrox captain James Tavernier that never materialised.
In fact, Zukowski would make just one appearance for the club... and than got us thinking how many Old Firm one-hit wonders have there been in both club’s history?
GlasgowWorld has looked back through the years to identify 10 players who joined either Celtic or Rangers and would go on to make a solitary first-team appearance before fading into obscurity:

1. Roy Carroll (Rangers)
Snapped up by Walter Smith as understudy to Allan McGregor in th summer of 2007, the Northern Irish goalkeeper made his sole appearance in a League Cup clash against East Fife before moving to Derby County the following January. Now an ambassador for Mental Health for FC Mindwell having battled with depression and alcohol during his own playing days. | Getty Images

2. Du Wei (Celtic)
Chinese centre-back made his one and only appearance on that fateful day in the Scottish Cup at Broadwood against Clyde in 2006. Making his debut alongside Roy Keane, Du Wei was substituted at half-time and never featured again. Headed back to China and had various spells at clubs in the Super League before retiring in 2018. | SNS Group

3. Andy Firth (Rangers)
A former Liverpool academy product, Firth was brought to Scotland by Steven Gerrard in January 2019 after a spell at non-league Barrow. Came on as a substitute in the final match of that season against Kilmarnock. Understood to be a big character in the changing room, hence why he was only released by the club last year. Now at Welsh side Connah’s Quay Nomads. Photo: Craig Foy - SNS Group

4. Luigi Riccio (Rangers)
Former AC Milan and Napoli assistant manager arrived in Glasgow alongside Rino Gattuso in 1997 and the midfielder would spend two seasons at Ibrox but made no real impact. His only league appearance came from off the bench against Motherwell. Riccio is currently No.2 to Rubén Baraja at La Liga side Valencia. | Getty Images