The 19-year-old, who joined Betis from America in January 2019, has scored twice and registered two assists in 29 appearances for his Spanish club in all competitions.
This term, the attacker has featured on 13 occasions for Rubi's side, scoring once and providing one assist.
According to reports in Spain, Spurs boss Jose Mourinho is an admirer of the teenager and could attempt to bring him to the Tottenham Hotspur Stadium during this summer's transfer window.
Lainez could allegedly be available for a figure in the region of €15m (£13m) despite the fact that he still has more than four years left to run on his contract in Seville.
The left winger has been capped on five occasions by Mexico.