I wouldn't look solely at the player stats from previous games because all of the players on the transfer market come from different leagues where you have different levels of competition.
You have to look at the player you're thinking about bidding on and deciding if he'd be a good addition to your team playing in your league.
Of course some players do just like to score more or foul more etc but generally i only take the previous games stats as a small indicator when looking on the transfer market.