Portman has a colorful résumé, and won more popular votes in 2010 than Strickland statewide. Plus, wasn't Strickland an unpopular governor? Anyway, this will be close, but my gut tells me Portman will narrowly prevail.
He was a so unpopular governor he lost only by 2 points, he carried many appalachian counties, that's turnout that sank him to be honest.
And even if it won't matter, Strickland's margin in 2006 was bigger than Portman's margin in 2010 (in %), but that won't matter because the contest will be different.
Portman isn't going to overperform the republican nominee, so whoever wins the WH (except if this is <1%) will make his party win the OH senate seat.