Although I am neither a player or architect, I am a parent of both.
Both son's attend a major D-1 SEC school with one being a Freshman baseball player and one being a 3rd year architecture student. Knowing first hand the time invloved for both I honestly see no way that you could be sucessfull.
Although I would assume that there are many differences in programs around the country the simple lack of sleep that an arcitecture student must indure, due to the work load, would not allow them to come close to giving their best effort on the baseball field in my opinion.
Pirate Fan makes many good points in his last statement. I can not tell you the number of times that projects have to be re-worked or simply scrapped due to the instructors changing something they want completed. Bottom line is there is very little free time and the projects, lab's and classes that are required simply do not work around baseball.
If you fall behind in architecture there is virtually no way to catch up. With the amount of time that is both officially and un-offically required for baseball (and this doesn't even include traveling during the spring)I would not recomend this.