I understand that you want to read subset of data from SAP using informatica Power Center? If yes the answer is yes you can do this.
"Data Subset for use with SAP" is a stand-alone product developed by Informatica, that is built using SAP technologies. This product is not integrated with PowerCenter. Although you could use PowerExchange for SAP & PowerCenter use case, you will need to build the mappings manually. But, this stand-alone product is easier to use for SAP experts as you use different transaction codes for this activity. Informatica does provide pre-built accelerators (also know as entities) for SAP CRM, SRM, and R3/ECC. Based on your requirement you might need to modify the entities (list of tables) and use.