Harry Robinson, son of Motherwell manager Stephen, has joined the Fir Park club until the end of the season.
Midfielder Robinson left Oldham City in January, having being on loan at Crusaders earlier this term.
The 19-year-old has played and scored once for Northern Ireland Under-21s.
Motherwell say the player will spend the next few months with the club's reserve team, which is coached by former Scotland defender Maurice Ross.
Ross has already included the younger Robinson as a trialist in matches and watched him score in a 5-3 win against Greenock Morton on Monday.
Meanwhile, David Turnbull played 60 minutes at Cappielow as he continues his comeback from preventative knee surgery, but had a penalty saved in the first half.