By Sonia Oxley MANCHESTER, England, Aug 15 (Reuters) - Manchester City have bought into new manager Manuel Pellegrini's attacking philosophy, but with no defenders signed yet their assault on the Premier League title may well be scuppered by goals leaking at the other end. City's back line has looked vulnerable in the close season and they go into their first match at home to Newcastle United on Monday having let in eight goals in their last three warm-up matches, including a 3-1 defeat by Arsenal on Saturday. ... More...