I remember that name! From stories like this!
First thought : Interesting - the Nats might have made another shrewd move catching a good player off of a couple bad years.
Second thought : First thoughts can be wrong.
I didn't realize it had been that long since Meredith had been good. 5 seasons to be exact. That 2006 season was really a fluke. It's hard to decipher much from his minor league numbers since the Red Sox rushed him up so quickly but his longer stays seem to show a pitcher who gives up a lot more hits than he did in that magical year. It's not that he's been bad since then, but high 3.00 ERA bullpen guys are a dime a dozen. Worse yet, in an effort to get that mojo back he's losing control. He's seen his BB/9 jump from 1.1 in the majors in 2006 to 1.9, 3.1, and 3.4 in subsequent seasons. Last year he had a 4.0 in the minors. That's bad. He did manage a 2.4 rate in the majors but probably uncoincidentally he couldn't keep the ball in the park anymore. Fancy stats show this wasn't just a fluke - he was giving up more flyballs then he ever did in his career.
I guess if you are willing to let him walk a guy or give up a hit, right now he can be useful if you absolutely don't want to give up a homer. Since he'll only be 28 next year it doesn't hurt to kick the tires on him, but since he's never had much strike out success in the majors (6.7 K/9 was his best rate - the Nats had 7 of 8 relievers who pitched more than 30 innings best that number just last year) even if you can get his wildness back under control he'll be nothing better than another arm in the pen.