Heyman broke the story on CBSSports.com, saying "The Diamondbacks and Brewers have been talking about possible trades involving Milwaukee veteran right-handed starter Yovani Gallardo, and one of the Arizona names that's surfaced in discussions is top pitching prospect Tyler Skaggs." However, he adds that discussions appear to be at an early stage, and quotes one person aware of the discussions as saying, "There's no traction at this point."
Gallardo was an All-Star in 2010, and had been a solid starter, since become a fixture in the Milwaukee rotation the previous season. Coming into this year, he had put up four consecutive campaigns of 30+ starts, averaging 196 innings, and with ERAs consistently in the 3.50-3.85 range (3.68 overall, a 110 ERA+). However this year, Gallardo has been significantly less effective, going 6-8 with a 4.78 ERA, an 83 ERA+. What's particularly concerning is a drop in velocity for the pitcher, with his fastball losing a mile per hour this season, in addition to the one lost in 2012. It may be significant that, earlier this year, Arizona managed to beat Gallardo for the first time in eight attempts.
Gallardo isn't cheap either. He is due to earn $7.75 million this season, jumping to $11.25 million next year, which seems a lot for someone whose performance this season has been at around the level of Trevor Cahill (who also has an 83 ERA+). Really, with Skaggs having apparently sorted out his issues in Reno, I would be more inclined to hold on and see what he can do - it seems likely he'll be called up to stand in for Cahill during the latter's stay on the DL. If Skaggs' numbers are anything like as good as the Reno ones, then a) trading him for Gallardo would be a hellish overpay, and b) the need to add a starter decreases significantly.
Perhaps more plausible is the source who told Jon Morosi of FoxSports.com that, as well as Gallatdo, the Diamondbacks were also interested in a number of Brewers relievers: John Axford, Jim Henderson and Francisco Rodriguez. The last-named has been outstanding, with a sub-one ERA in 19 appearances this season, striking out more than a batter per inning. He'd certainly seem to provide a boost for the bullpen, which has been wobbly of late, but would likely be only a rental, as he's on a one-year contract.
Anderson closed in Rodriguez's absence and has been solid, with a 2.05 ERA in 31 relief appearances He spent nine years in the minors, and currently has less than one year's service time, so there would be a lot more control involved there, even if he is now aged 30. Axford is the former Brewers' closer, who saved 46 games in 2011, and 35 last year, despite being much less effective in 2012. He was a Super Two this year, and is earning $5 million, with three more seasons of control before free-agency.
We'll see whether these are just rumors, or if Kevin Towers feels the need to pull the trigger on a deal to bolster the Diamondbacks pitching staff for the second half of the season.