Here's the workaround that I did:
Install yum-utils
and find out what files are in the package php53
# yum install yum-utils
# repoquery --list php53
/etc/httpd/conf.d/php.conf
/usr/lib/httpd/modules/libphp5.so
/var/lib/php/session
/var/www/icons/php.gif
Install the yum-downloadonly
plugin for yum
# yum install yum-downloadonly
Download the php53
RPM package without installing
# yum install --downloadonly --downloaddir=/home/dump php53
Unpack the RPM package
# rpm2cpio php53-5.3.3-22.el5_10.x86_64.rpm | cpio -idmv
Copy the files from the RPM package to its relevant place on the server
# cp php.conf /etc/httpd/conf.d/php.conf
# cp libphp5.so /usr/lib/httpd/modules/libphp5.so
... etc
No httpd
installed!