Overall reaction seems positive in the news thread. I wanted to run the numbers, though, just to see.
What the Reds are Paying:
Assuming the signing bonus is paid evenly over the three years ($1.7M/yr), and making some guesstimates about current and future WAR/$ exchange rates, the Reds are paying:
$7.7 M in 2010 @ $4.5 M/WAR = 1.7 WAR
$8.2 M in 2011 @ $4.7 M/WAR = 1.7 WAR
$8.2 M in 2012 @ $5.0 M/WAR = 1.6 WAR
Total contract value: 5 WAR over life of contract.
How Rolen Projects:
Offense: I averaged the CHONE and ZiPS projections for Rolen in 2010. That gives this projection: 463 PA's (66% playing time), 0.277/0.352/0.432 slash line, 11 HR, 0.347 wOBA, 4.8 RAA after park adjustments = 0.51 WAR. An aging but still effective hitter, at least when he's in the lineup.
Fielding: both Jeff Zimmerman's UZR/150 projections as well as CHONE's fielding projections have Rolen at 7 RAA per season. Fan Scouting Report had him at +18 runs last season (weighted average of his totals from TOR and CIN fans). Average of the three approaches puts him at 10.6 runs per season. Given the playing time estimates above, that projects him at 7 RAA = 0.75 WAR. Still an excellent defensive 3B.
Position Adjustment: +0.25 per full season for 3B, prorates to +0.17 WAR given the playing time estimates.
Replacement level: 2 WAR/season in the NL, which prorates to 1.3 WAR given the playing time estimates.
Overall, assuming 0.5 win/yr aging:
2010: 0.51 + 0.75 + 0.17 + 1.3 = 2.7 WAR
2011: 2.2 WAR
2012: 1.7 WAR
Total expected: 6.6 WAR
Given his age and injury history, you can argue that we should use slightly higher aging rates than this. You can also argue that free agent salaries are actually coming in lower than $4.5 M per WAR this year (though I think it's too early to make that call). Nevertheless, I think it's fair to say that this deal is, at WORST, a market-even deal....and most likely represents a nice little surplus. Congrats to the Reds on a nice deal.
Update 12/20/09: I noticed an error in how I was applying a park correction to his offensive projection. This has been fixed above. It did not change the conclusions, but did pull 0.2 WAR/season off of his projections. I apologize for being a dork.