Rivera, 32, was shipped from Cleveland to Arizona in May for cash considerations.  The D'Backs went on to designate the veteran for assignment in June and release him in August. 

From 2006 through 2008, Rivera found a role in the Nationals bullpen as he posted a 3.72 ERA with 6.4 K/9 and 4.1 BB/9.  However his fortune turned in 2009 when he delivered a 6.10 ERA with 4.9 K/9 and 3.3 BB/9. 

• The Padres acquired lefty Tyler Lumsden from the Astros for future considerations.  The former first-round pick has already tossed over ten innings for the Double A San Antonio Missions.  Lumsden was well-regarded a few years ago, ranking fifth among Royals' prospects in BA's '07 Handbook.
• The Red Sox released pitchers Randor Bierd and Kason Gabbard.  Bierd came to the Sox in the January '09 David Pauley trade, while Gabbard was sent to Texas in July of '07 in the Eric Gagne deal and later reacquired.
• The Diamondbacks released reliever Saul Rivera.  He'd been designated for assignment on June 8th.

As a group, D'Backs relievers have a 7.19 ERA, so the team continues looking for bullpen arms. Boyer, 29 next month, was part of the problem for manager A.J. Hinch early in the season, when he posted a 7.82 ERA in 14 appearances. But the right-hander returned to the minors and pitched well. Boyer walked one and allowed five hits in six innings, striking out nine.

Rivera, 32, has a 0.53 ERA, 5.8 K/9, and 3.7 BB/9 in 17 Triple A innings so far this year.  He's got similar peripherals over 275.6 career big league innings, leading to a 4.05 ERA.  Rivera was released by the Nationals in December (on his birthday) to make room for Brian Bruney.  He later signed a minor league deal with the Indians.

Howry, 36, was signed by the D'Backs to a one-year, $2.25MM deal in December.  In 14.3 innings this year, he sports a matching 3.8 in terms of home runs, walks, and strikeouts per nine innings.  That's not an effective formula.  Arizona's bullpen has a 7.68 ERA in 104.3 innings, so changes were necessary.  Aside from Aaron Heilman, everyone has struggled.

The 32-year-old Rivera posted a 6.10 ERA, 4.9 K/9, and 3.3 BB/9 in 38.3 big league innings this year.  He tossed another 45.6 innings at Triple A.  He was fairly useful in the three previous seasons.