San Francisco 49ers head coach Jim Harbagh has heaped praise on Indianapolis Colts quarterback Andrew Luck, whom he used to coach when the pair were at Stanford together.

Harbaugh said that Luck's most important attribute is that he puts the team ahead of being an individual, and with this mentality can see the player continue to grow in the NFL.

"It's a powerful strength [to be a team player]," Harbaugh told the Colts' official website. "He's so smart. Andrew understands the game of football so well.

"He understands the team that plays the best has the best chance to win, so it's a team game. He's smart enough to understand all those things at such a young age.

"Growth-wise, he got better. That's going to happen. He's got a great work ethic. He has a great love of the game. He loves weight-lifting. He loves the practices, the running, the meetings. He loves football. Andrew has a great competitive heart and a desire to be great. You're going to see that growth from him every year."

Luck was drafted by the Colts in 2012 and has played every regular season game for the club.