5:13pm: Renck also tweets that when asked about the possibility of trading Michael Cuddyer, Monfort replied, "No way. Not happening." Cuddyer is in the second year of a three-year, $31.5MM pact with Colorado and has enjoyed a monster season. To this point, he's hitting .330/.391/.568 with 16 homers. That production led to his second All-Star berth and first Home Run Derby, where he narrowly missed the finals.
3:27pm: The third-place Rockies have cooled off after a red-hot start to the season, but they're still just 4.5 games out of first place in the NL West and 7.5 games out of a Wild Card position. However, Troy Renck of the Denver Post reports that owner Dick Monfort said in a letter to season-ticket holders that the team will not surrender top prospects for a pitcher it is simply renting for a few months (All Twitter links).
The Rockies have been connected to a pair of prominent rentals thus far -- Matt Garza and Jesse Crain. However, if Monfort's statement holds true, Garza certainly won't be joining the Rockies, as he would likely require a package of elite prospects. As a reliever who is currently on the disabled list, Crain's value is currently lower, so it's conceivable that the Rockies could land him without surrendering their "top" prospects. That, of course, is my own speculation, as opposed to a comment from Monfort himself.
There are still numerous pitchers with multiple years of control that the Rockies could pursue. For more info on that, check out Tim Dierkes' recent look at the trade market for starting pitching and my analysis of the market for right-handed relievers.