The tight end finished the regular season with 61 receptions for 669 yards and seven touchdowns, his best figures during his three seasons in the NFL.
The quarterback told the Ravens' website: "I don't know how he's improved. He's just a good player.
"I think [the Ravens coaching staff have] seen he can play so they make him a bigger part of the offense. He's produced when he's gotten the chance."
The Ravens face the San Francisco 49ers in the Super Bowl on Sunday.