This is the coolest thing ever. I caught this while the Idaho Famous Potato Bowl (seriously?) was on the TV at a bar and found this on Youtube later. Whoever thought this up is a genius. Think it would work in tennis?
Oh, yes, I can see pro tennis players being thrilled about being handed tennis balls covered in dog slobber. 
The minor league baseball team here has a couple of Labradors that fetch the dropped bats after a player gets a hit. They also take little buckets of new balls out the the umpire when he needs them.
I like it. I also like the Potato Bowl. It’s a throwback to the good old days of the Orange, Sugar and Peach bowls that promoted local agriculture and actually represented a region. Better than the fucking Insight Bowl, Beef ‘O’ Brady Bowl, Kraft Fight Hunger Bowl and the Godaddy.com Bowl.
Brought to you by Carl’s Jr.
I just hope the dog handler doesn’t miss a long return in the making, and send the dog out there prematurely to get plastered by a bunch of football players (or conversely the dog seizes a fumble and plays keep-away for the next half hour). 
Chuckle. Based on that clip, it does look like the handler waits for the kickoff return to be blown dead before he sends the dog out on the field.