I'm a relocated Twins fan. I don't think he will settle into a regular OF rotation. He can drive the ball well, probably more valuable in your line-up playing at home, but gauging his daily playing time and his favorable matchups is probably more than I'd want to invest for the return.
I had and used Kevin Millar, who is very productive, but will leave you short in games played like Kielty. I had to cut him loose over Payton to nab Berkman off waivers.

buh-bye waiver priority.
Kielty may be worht having for short periods of time to fill in for injury, or slumpers, but is not a long term solution to anybody's OF situation.