Funny, my GS loves Frisbee and is quite good at it (when she bothers to KEEP HER EYE ON THE FRISBEE!). Sometimes she does amazing things to catch it! Maybe it's a Herding Dog thing.
When she was a baby she was a total wimp (she is basically a bad wimpy GS), but things like balls and frisbees she knew she wanted to try, just was afraid at 1st to see them coming at her. So she'd be passive and let it land then go pick it up. Eventually she grew to understand she can catch them and nothing bad will happen. Now she's a linebacker and gets broken lips from *blocking* (if she can't catch, she'll block) heavy kicked balls.
1 thing that really helped w/HER was having good balls and frisbees. 2 years ago I stumbled upon DOGOBIE. They are WONDERFUL frisbees made for dogs - soft rubber and really flat except edge rims. That really emboldened Tara. So now she'll go for any flying disk w/o fear. You should try Dogobie (by Aerobie); it's great for introducing dogs timid about hard flying things.
I saw those Dogobies at the vendors section at a show earlier this year. I should of grabbed a couple then. Would be an easy thing for the min-pin to handle although I don't think there is anything he's afraid of...seriously...except for cold rain 8>)