Huston Street (Rockies) - Street appeared to be a lock to go a few weeks ago, and it seemed likely that the Rockies wouldn't even wait until the deadline before making a move. However, their recent surge, combined with the loss of former closer Manny Corpas, is going to make trading him much more difficult. At the very least, it figures to go down to the deadline now. Street's value is sky high at the moment thanks to 16 saves in 17 opportunities and a 35/9 K/BB ratio in 31 innings. Odds are that it will only drop as time goes on. Even if Street remains this effective, there won't be as much demand after the year, since he'll probably make $7 million or so next season in what will be his final year before free agency.
Chad Qualls (Diamondbacks) - While he's avoided the DL, Qualls has experienced some forearm issues of late that have taken a toll on his ERA. He'll need to get past those if the Diamondbacks are going to receive the kind of offer that would make it worth moving their closer. Qualls is under control through 2010, and his modest price tag will make him quite attractive. If he finishes with 30 saves this year, his salary could jump to $5 million or so next year, but he'd be in line for less if he's relegated to a setup role with a contender.
Danys Baez (Orioles) - It seemed highly unlikely a few months ago, when Baez tried and failed to crack the Baltimore rotation, but he's finally earning his salary in the final season of his three-year, $19 million contract with the Orioles. The league has hit just .183 off the right-hander, allowing him to amass a 3.22 ERA in 36 1/3 innings. He's more of a seventh-inning guy than a true shutdown setup man, but he figures to come cheaper than most of the other relievers on this list.
George Sherrill (Orioles) - Sherrill has allowed just one run in 18 appearances since sort of losing his job a month into the year (the Orioles indicated that they were going to a committee, but it never materialized). He now has a 2.20 ERA, and he's 15-for-17 in save chances. It looked like the Orioles blew it last year when they failed to sell high on Sherrill and then watched him struggle and lose most of his trade value after a poor second half. They could always do it again, but they do have more depth now and they should be able to better cover his loss.
Takashi Saito (Red Sox) - The Red Sox have a surplus of relievers, and Saito hasn't pitched as well as his 2.59 ERA in 24 1/3 innings indicates, though he has improved considerably over the last month. Making a deal tricky is that his salary is due to keep growing. It's currently at $3.5 million, and he could guarantee himself as much as $7.5 million if he remains healthy all season. Even the Red Sox don't want to commit that much to their fourth- or fifth-best reliever.
Rafael Betancourt (Indians) - Kerry Wood figures to stay, but the Indians should move Betancourt, who had lowered his ERA to 3.71 before landing on the DL with a groin strain at the beginning of the month. He's due to return in early July, giving him a few weeks to rebuild his value. The Indians probably won't ask for much in return if it means shedding the rest of his $3.35 million salary.
LaTroy Hawkins (Astros) - The Astros probably won't write off the season -- which means fellow free-agent-to-be Jose Valverde is likely to stay -- but if they see the opportunity to trade Hawkins for immediate help, they could take it. Since joining Houston, Hawkins has a 1.92 ERA in 51 2/3 innings. American League teams will want to stay far, far away.
Renyel Pinto (Marlins) - Pinto's ERA stands at 2.31, but he hasn't gotten there by retiring lefties (.308 average against) and Dan Meyer has supplanted him as the top southpaw in Florida's pen. That he'll be arbitration eligible for the first time this winter only adds to the chances that he'll be moved, though at $1 million or so, he's hardly set to break the bank.
Cla Meredith (Padres) - The Padres could get a whole lot in return for Heath Bell, but he'll be reasonably inexpensive for another year. Meredith, on the other hand, has just about outlived his usefulness with arbitration eligibility on the way. He has a 2.89 ERA this season, but it comes with a 1.57 WHIP and 14 strikeouts in 28 innings. The Padres no longer use him with leads, as evidenced by the fact that he hasn't picked up a hold since April 16. His ability to induce grounders would be of more use in a smaller park.
Ron Villone (Nationals) - The Washington pen, so brutal for two months, suddenly has Mike MacDougal, Villone, Joe Beimel and Julian Tavarez all throwing well. Of course, no one from the group can be counted on for the long haul. Three of the four will be eligible for free agency at season's end, and MacDougal, who is making $2.65 million this year under the terms of his deal with the White Sox, would be costly to keep in arbitration if he remains effective. The Nationals should deal one or two of the veterans of the group if decent prospects are offered, and the two lefties are the most likely to go.