Drew, a shortstop, missed three months this season recovering from a gruesome broken ankle he sustained last summer. In his last full season, in 2010, Drew played 151 games and hit .278 with a .352 on-base percentage. He had 15 home runs that year, second among National League shortstops behind only Troy Tulowitzki.
In 13 games this season, Drew, 29, is hitting .233.
Roberts, a utility player, has appeared in 76 games this season at second base and third base. The 31-year-old is hitting .239 with a .287 OBP.
From the Fox Sports article:
It's not clear how advanced the talks are, but sources say there has been dialogue between the clubs on scenarios involving one or both players.
Drew, 29, has played exclusively shortstop in the major leagues. Since he's coming off a leg injury, it's doubtful the Tigers would expect him to switch positions if he is sent to Detroit. So, the Tigers' assessment of whether Drew can handle the rigors of shortstop will be key to their willingness to trade for him. Neither Drew nor Jhonny Peralta (Detroit's current shortstop) is regarded as an elite defender.
The article goes on to say that the Diamondbacks could ask for Peralta in return, partly because his contract has a $6 million club option for 2013. On the season, Peralta is hitting .267 with a .344 OBP in 81 games.