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8/27/2013 10:42 P.M. ET

Bloomquist could return for finale vs. Padres

PHOENIX -- Designating Jason Kubel for assignment Tuesday opened up the possibility of the D-backs activating veteran infielder Willie Bloomquist from the disabled list as soon as Wednesday. David Holmberg took the opened roster position Tuesday to make a spot start, but the club will not need a sixth starting pitcher come Wednesday.

Depending on how much the D-backs used their bullpen Tuesday, the club would most likely make another roster move for a position player Wednesday. Bloomquist, on the shelf since June 28 with a broken left hand, was with Triple-A Reno on a rehab assignment.

"Kind of right now, we're going to see how we get through this game tonight and see what our needs are," D-backs manager Kirk Gibson said before Tuesday's game. "If we have to go get a pitcher, we'll probably hold [Bloomquist] off and have him play another game down there."

Bloomquist hit 6-for-12 in four games with the Arizona League (Rookie) D-backs last week and went 1-for-3 on Monday in his first game with Reno.

Kubel designated for assignment by D-backs

PHOENIX -- Relegated to a pinch-hitting role less than a year after posting a 30-home run season, Jason Kubel's gradual descent from lineup mainstay to expendable asset came to an end Tuesday as the D-backs designated the veteran outfielder for assignment.

Arizona needed to make room on its roster for Tuesday's pitcher, David Holmberg, and the club decided it was time to part ways with Kubel, who had started just twice since Aug. 3.

"It's a hard thing to do; he has had a great career up to this point," D-backs manager Kirk Gibson said. "It didn't work out the way we wanted to; he struggled this year, and his playing time was drying up. We went in a different direction here, and it's only fair for him to try to catch on with somebody and get an opportunity to help someone else."

Kubel is now in a 10-day waiting period, during which he is likely to be traded or released by the D-backs. Other teams will first have an opportunity to claim him off waivers, and then the two clubs would have to work out a deal. In order for Kubel to be eligible for a postseason roster, however, the trade would have to occur before Aug. 31 at 11:59 p.m. ET.

The 31-year-old is in the final year of a two-year, $16 million deal and is making $7.5 million in 2013. His contract also calls for a $1 million buyout of his mutual option for 2014.

"I'm confident I can still play, but we'll see if I get a chance," Kubel said. "Hopefully I can play some meaningful games for somebody else."

Kubel, who signed as a free agent with the D-backs after the 2011 season, had a productive first year in the desert in 2012, hitting .253 with 30 doubles, 30 homers and 90 RBIs in 141 games.

This season, however, has been a completely different story. Hobbled all year with knee, back and leg issues, Kubel never really found a rhythm at the plate, and his production suffered. In 241 at-bats, he posted a .220 batting average and a .612 on-base plus slugging, both of which are career lows.

"He has worked hard, he tried to figure it out, but it's a very tough situation when you work and you work, then you try to take it up there and you have limited at-bats," Gibson said. "It's basically he tries something in a pinch-hit at-bat, and if it doesn't work, it grinds on you."

Kubel, standing at his locker in the D-backs' clubhouse for the last time after hugging his teammates goodbye, acknowledged that 2013 had been the most trying season of his career.

"Yeah, not even close," he said. "Just trying to stay healthy and stay in the lineup, it was a rough year for that. It's hard to figure everything out; I just couldn't put together why it happened. ... It's tough, but it's part of the business. I wasn't helping my case anyways. That's just how it is, I'll just try to keep going."

Six top D-backs prospects named to Fall League

PHOENIX -- Hoping to follow in the footsteps of Didi Gregorius, Adam Eaton and so many others, six D-backs prospects were named to the Salt River Rafters roster of the Arizona Fall League on Tuesday. Jake Barrett, Andrew Chafin, Jake Lamb, Nick Ahmed, Matt Stites and Mike Freeman will join prospects from the Blue Jays, Cardinals, Rays and Rockies on a team that will play its home games at Salt River Fields in Scottsdale, Ariz.

The youngsters will begin play Oct. 8 in the prospect-rich League, which has graduated more than 60 percent of past participants to the Majors and includes representatives from all 30 clubs.

Five of the players the D-backs will send are ranked by MLB.com among the top 20 prospects in the club's farm system, with Barrett at No. 7, Chafin at No. 8, Lamb at No. 11, Ahmed at No. 13 and Stites at No. 17. Arizona will announce a seventh prospect to join the others at a later date.

Barrett is a flame-throwing right-handed reliever who has burst onto the scene after the D-backs selected him in the third round of the 2012 First-Year Player Draft out of Arizona State. In just his first full professional season, Barrett is already the closer for Double-A Mobile, boasting a 0.42 ERA over 21 2/3 innings with 13 saves. He could contend for a spot in the D-backs' bullpen as soon as next year.

Chafin, a first-rounder in 2011, has started 20 games for Mobile, posting a 10-7 record and a 3.04 ERA. Recently acquired from San Diego in the Ian Kennedy trade, Stites will pitch for the first time in his new organization after a season-ending appendectomy earlier this year.

Highlighting the position players the D-backs are sending is Ahmed, who was part of the blockbuster Justin Upton deal with Atlanta in the offseason. The shortstop has hit .229 in 130 games with Mobile in 2013. Lamb, a third baseman, has hit .320 in 57 games with Class A Advanced Visalia.

Snake bites

Aaron Hill returned to the lineup Tuesday against the Padres after being held out the previous two games. He left Saturday night's contest in Philadelphia in the bottom of the seventh because of mild tightness in his groin.

• In six appearances with Triple-A Reno since being optioned, David Hernandez has worked 6 2/3 scoreless relief innings, allowing two hits and striking out seven.

"He has been doing fine," Gibson said. "He's throwing a lot of sliders; he's working on that down there."

Tyler Emerick is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.