University of Southern California, Cal-Berkeley, Cal Poly san Luis obispo, Rice, Washington, UNLV all have excellent baseball and architecture programs. I think Harvard and Yale also fit the bill.
I will tell you though, and others on this board have said their experience is otherwise, when my son went through the process he was specifically told by each school he spoke with on this subject that it was not possible to play any sport and major in architecture. To this end, we spoke with coaches, admissions officers and the Deans of two different architecture departements.
The primary reason is that architecture classes have labs typically every afternoon and you need to be at games or practice every afternoon. In hand with this, arhitecture is easily one of the most time consuming majors one can pursue in college.
You may find a different answer, do your homework and check with the schools you become interested in. We did not find one that would allow my son to do both, maybe you'll have better luck.