Former Leeds United manager Neil Warnock said on the Alan Brazil Sports Breakfast show on talkSPORT on Monday morning that Son Heung-min is not a top-class player.
Warnock is impressed with the performances of the South Korea international attacker for Spurs so far this season, but he does not think that he is a world-class footballer.
"I think Son is a good lad," the former Crystal Palace boss said on the Alan Brazil Sports Breakfast show on talkSPORT on Monday morning.
"He is not top class, but he works his socks off, and I think Harry Kane will come good."
Son, who can play as a forward or as a winger, joined Tottenham from German club Bayer Leverkusen in the summer transfer window.
The 23-year-old was one of the better players in the Bundesliga last season and helped Bayer finish fourth in the league table.
During the 2014-15 campaign, Son scored 11 goals and created 39 chances in 30 league appearances.
Son had a pass accuracy of 76% and a shot accuracy of 54%, and won 30 headers, 49 dribbles and 30 tackles.
So far this season, the former Hamburg player has scored one goal and created two chances in two Premier League games for Spurs.
The South Korean has a pass accuracy of 77% and a shot accuracy of 67%, and has won three dribbles and three tackles.
Son has scored two goals and created one chance in one Europa League appearance for Spurs this campaign.