No, he would still remain a one star, but would just take longer to get to 2* as he's that poor (I saw one team that had a 1* player with a quality of 12(!!!!!!!!!!!!!) in his squad. They were level 5).
When I was L15. There was a team in my league that had a 30 y.o. 2nd choice GK that had 46 quality and their main GK was a scout!