Tom Seaver was definitely a spring training instructor in 1999 however I don't think in 1990 because of his duties as a Yankee broadcaster as everyone noted in the previous posts.

My guess is this may be an Old Timers Game Jersey if anything.

I like Nick's approach to try to ask Seaver at the May 21 show as he is usually good about remember his game used stuff.

I did send an email to Seaver (from the contact Tom email address at www.tomterrificseaver.com with the ebay link to this jersey and let's see if we get any response.

David