He has a good shot at beating either Lee or the Governor..he’s clearly running for something in 2016, on the other hand Love has a real good shot at winning his seat in the house.
This practically hands this seat to Mia Love, black, female Republican. Dem’s poured outside money to keep Mia out in 2012 (she lost by about 500 votes), but Matheson probably saw the writing on the wall for 2014, and figured he would avoid tarnishing his name with a loss. Matheson remains electable when the winds are blowing his way - but that might not be the case in 2016 either (after 8 years of Obama stinking up the Dem brand).