You should be fine. Jennings could be a good WR2. No problems with your RB's either. I hate Mathews but that's only because I drafted him last year. I don't see how that team doesn't make the playoffs. Especially considering Aaron Rodgers is probably going to throw for like 5,000 and 45 TD's or something stupid like he always does. It was a good year to draft at the 10-12 spots.
Here's my recently completed draft. $100 buy in. 12 man PPR. Had the 2nd overall. Kept Cruz and Sproles. Had to waay overdraft Matt Ryan because my leauge loves to draft QBs very early even though it's 4 pts. passing TD. 6 for rec/rushing TD. PPR. 1 QB, 2 RB, 3 WR, 1 Flex, 1 TE, 1 K, 1 D.
QB: Matt Ryan, Ben Roethlisberger
RB: Jamaal Charles, Darren Sproles, Darren McFadden, Fred Jackson, Kendall Hunter
WR: Victor Cruz, Vincent Jackson, Kenny Britt, T.Y. Hilton, DeAndre Hopkins
TE: Vernon Davis, Jermaine Gresham
K: Garrett Hartley