I bought two strikers at 4-5am one morning earlier this season, starting details below:

Click image for larger version.  Name: PC Anthony Petrovski.jpg  Views: 29  Size: 55.7 KB  ID: 51295Click image for larger version.  Name: PC Liam Cashman.jpg  Views: 29  Size: 57.3 KB  ID: 51296

Petrovski started scoring immediately, until he got injured (currently 4 games 3 goals 1 assist), but Cashman took 4-5 games to get into the groove and is now banging them in regularly (currently 14 games 6 goals 1 assist)...

I think an average of a goal every 1-2 games is not stellar, but as long as he's contributing to the game and others are scoring too then I'm happy with it. One of the duties of a striker is to get in amongst the defence and stir them up a bit. If they're concentrating on the one that should be scoring then others have got a chance to sneak in and put the ball in the net...