Gene J. Puskar/Associated Press

The Pittsburgh Pirates are in the thick of a playoff push early in September but show signs of fading after losing three straight games to division opponents. What has the front office done to bolster the roster to make a push toward October?

They called up names like John Holdzkom, Bobby LaFromboise and Chase d’Arnaud. One of those players (LaFromboise) is already on his third team this year, another (d’Arnaud) is getting his first major league action since 2012, and the other (Holdzkom) has never before pitched in Major League Baseball.

It was an underwhelming announcement from the front office during a time when other teams are calling up the best prospects in their farm system.

Some of those Pittsburgh Pirates prospects, like Gregory Polanco and Casey Sadler, also got promoted recently and already have experience playing for the team this season.

But don’t expect great results coming from either of those players. Sadler is already on his fourth stint with the team this year while Polanco has a .240 batting average in 250 at-bats.

The team also recalled Jeff Locke, who promptly issued five walks and gave up four runs in three innings pitched in a loss to the St. Louis Cardinals. He put the team into a hole it couldn’t climb out of en route to a second consecutive loss to the Cardinals.

Fans already know what they’re getting with names like Locke and Polanco. This column will focus more on the lesser-known names who will have an impact, for better or worse, on the team as it races toward the finish line.

John Holdzkom

Perhaps the best story coming out of these September call-ups is the addition of John Holdzkom, the 26-year-old who the Pirates plucked out of the Independent League on June 23.

He didn’t take long to make his mark. The 6’7 righty induced three strikeouts in the eighth inning against the St. Louis Cardinals on Sept. 2 in the first major league action of his career.

That’s not the interesting part, however. According to MLB.com's Tom Singer, Holdzkom is bringing back a pitch called the palmball to the majors.

'Our guy is the only one who throws one now,' manager Clint Hurdle declared of a pitch that was very popular among big leaguers at one time -- before the wildfire spread of the split-fingered fastball. Both pitches have a similar downward pattern, but the palmball puts greater stress on the elbow.

The towering relief pitcher hasn’t had much time in the Pirates’ farm system, but he’s made the most of it. Holdzkom pitched to a 2.49 ERA in 21 innings since being signed in late June. He throws a palmball that can top out in the high 90s.

He might have been plucked from the Independent League, but Holdzkom could provide a serious boost to the bullpen down the stretch.

Casey Sadler

It’s not fair to dismiss Sadler’s skill set based on his limited time in the big leagues this year despite the fact that he’s pitched to a 7.71 ERA in nine innings.

As previously mentioned, this is already Sadler’s fourth stint with the team this year. However, the 6’4 righty has had an impressive year in Triple-A Indianapolis, posting a 3.03 ERA in 21 starts this season.

He finished the season with an 11-4 record, and his 1.19 WHIP was the second-lowest among all International League pitchers.

Drafted in the 25th round in 2010, Sadler’s fastball typically tops out at around 91.5 mph, and he also mixes in a slider and changeup.

As John Sickels of SB Nation reported in May, Sadler won’t wow you with his electric stuff, but he could provide a new arm in a faltering bullpen.

“He's not generally overpowering," Sadler writes, "but he'll get some ground balls, throws strikes, and can pitch in any role.”

Sadler is just one of several prospects brought up to help bolster a bullpen that has a ton of questions surrounding it. Don’t look for him to add any meaningful depth or contributions to this team going down the stretch.

Bobby LaFromboise

This 28-year-old lefty has barely been in the organization for a week but now finds himself on a big league roster for only the second time in his career.

The Pirates claimed LaFromboise off waivers in late August and immediately optioned him to Indianapolis. His only prior major league experience came last year with Seattle when he pitched to a 5.91 ERA in 10 games.

He’s compiled a 4.75 ERA in 53 innings this year in the minors and doesn’t bring anything special to the Pirates.

As the folks over at Bucs Dugout said recently, the lefty throws sidearm with a fastball that barely tops out in the low 90s. He mixes in a slider and a changeup in his repertoire and will get limited time coming out of the bullpen from the Pirates.

His career up to this point has been rather nondescript, a script that likely won’t change now that he’s in Pittsburgh.

“He had a big season in the minors in 2012, but otherwise has been very nondescript throughout his career," WTM of Bucs Dugout writes. "Except this year, when he's been pretty bad. “

Chase d’Arnaud

Rounding out the list of unspectacular players getting the call to Pittsburgh, Chase d'Arnaud’s addition to the lineup is interesting if only for the fact that the Pirates designated Michael Martinez for assignment to clear space on the roster.

D’Arnaud, a 27-year-old infielder drafted in the fourth round of the 2008 draft by the Pirates, has shown little in his professional career, compiling a .208 batting average in 149 at-bats in the big leagues.

His minor league starts aren’t very impressive either, as d’Arnaud has hit for a .260 career average in nearly 2,500 at-bats. He’s also been caught stealing 13 times this year in 43 attempts, a sign that his once-promising speed is dissipating as his age climbs.

Charlie Wilmoth of Bucs Dugout recently warned Pirates fans not to get excited about d’Arnaud. His quiet bat and mediocre skill set likely won’t add much of anything to the team this September, even if he is a better option than Martinez.

“He hasn't hit much since all the way back in Class A Advanced, and he's completely flatlined at Triple-A," Wilmoth writes. "On top of that, Neal Huntington recently said almost flat-out that he didn't care for d'Arnaud as a player."

Wilmoth projects that d’Arnaud will likely only make one or two starts down the stretch, and “hopefully not even that.”

That’s the kind of glowing praise fans were hoping for with this most recent round of September call-ups.