tom
My first trip with a camera to a Jays game was the 1985 LCS with the KC royals.
I took my KX (film for those who confuse KX with K-x) and a Vivitar MC 400mm F5.6
I shot from the old grandstand at CNE stadium more than 400 feet from home plate, and had shots where the individual players were pretty small but recognizable on film.
Therefore if you want to have general action shots, a 400 is not a bad option (I believe you have one of those in you bag of K mounts)
In the Skydome (I still call it that) you can get closer, at a low cost.
I find the second deck on the left field foul pole is typically $24-$26 on game day, and you have a good view at 325 feet from the plate, and can usually get seats in the first row on the railing. This is key because you are above the field level seats, and in the first row, there are no fans in front. Using my favourite formula
Image size = subject size * FL / Distance
a 6 foot person at home plate will be 8 mm high on your sensor or roughly half the frame.
Clearly moving in helps, but unlesss you are looking for facial expressions and tight crops, you want the image to be at most 16 m high (person standing) hence no closer than about 50 meters or 160 feet. The first or third base lines will be a little close for a 400mm in this case.
The best solution would be if you can be somewhere on the second level, first row, with pre-ordered seats and then pick your lens, 200, 300 or 400 depending on how far away (down the foul line) you are
Remember the dimensions.
the foul pole in toronto is 325 feet from home plate, the bases are 90 feet apart, and there is about 50 feet of field between the stands and first / third base.
Depending on seats any of your birding lenses would do and I know you don't have an issue with MF