I'm not sure why the Reds gave Jack Hannahan $2M guaranteed when he was projected to make less than that in arbitration. But apparently there was a market for him. And it's not our money. Unless ticket prices go up. Or your kid inexplicably begs you to get him a Jack Hannahan shirtsey.
In any case, Jack Hannahan is probably not that good. Which is why he'll be a bench player. But, like Jason Donald, he was pretty good in 2011. Unlike Jason Donald, he's on the wrong side of 32. I'm not that optimistic he'll be much better, moving from one Central division to the other, but there are a few mitigation factors.
For one thing, Miguel Cairo "slashed" .187/.212/.280 last season. Hannahan has a similar skillset in that he'll be a corner infielder. Cairo was probably a more reliable 2B, but Hannahan can play some middle infield in a pinch. He made 7 appearances at short last season. So, to improve this bench spot, he just has to show up.
Hannahan also hits lefty. With the addition of Choo and retention of Paul, the Reds have gone a long way to evening out their right-leaning tendencies. His career splits actually only barely favor match-ups against right-handed pitchers, but maybe that'll count for something.
Also, Great American Ballpark is not the Prog/Jake. Hannahan hits dead pull shots which would probably be out of both parks, but maybe some of the atmospherics will help. If he opens up a little more of right field, he could get a bump.
I'm not sure how much better the Reds could have done in a back-up infielder. Maybe they should have let Donald spell Cozart at short and plug Henry Rodriguez into the Cairo role. But there's no question in my mind that infield bench has been improved. From "worst" all the way up to "probably competent."