© 2014 MLB Advanced Media, L.P. All rights reserved.

8/14/2014 6:00 P.M. ET

Walker very close to return to Pirates' lineup

DETROIT -- Neil Walker's return to the Pirates' lineup seems imminent.

The second baseman, who has missed 12 of the club's last 13 games with lower-back tightness, stood in the on-deck circle as the final out was made Thursday. Had the game been extended, Walker would have pinch-hit.

"We felt he was a usable player off the bench today," manager Clint Hurdle said. "We're optimistic he might be a little more than that tomorrow.

It seems possible, and perhaps even probable, that he'll be in the starting lineup Friday night, when Pittsburgh begins a three-game series against the Nationals.

Mercer leaves game with right forearm tightness

DETROIT -- Pirates infielder Jordy Mercer exited Thursday afternoon's game against the Tigers in the seventh inning with what manager Clint Hurdle called right forearm tightness.

When asked whether the injury might sideline Mercer for an extended period of time, Hurdle responded, "I'm not a doctor."

When Pittsburgh came out of the dugout for the home half of the seventh, Josh Harrison scooted over from third base to take Mercer's spot at shortstop, and Jayson Nix took Harrison's post at third.

Mercer went 0-for-2 Thursday with a strikeout against Detroit starter Max Scherzer.

Pirates consider options to improve bullpen

DETROIT -- After Stolmy Pimentel failed to record an out in Wednesday night's 8-4 loss to the Tigers, manager Clint Hurdle said his team is "actively look to improve our club every day."

One form in which that help could come is Vin Mazzaro, who is pitching out of Triple-A Indianapolis' bullpen. Mazzaro has made 62 appearances for the Pirates between this year and last.

"That's one guy we've had conversations about," Hurdle said. "We're looking for guys whose stuff is crisp."

Hurdle noted that the challenge in evaluating his Triple-A pitchers, not just Mazzaro, is determining how their numbers will translate to the big league level. The club's history with Mazzaro makes him less of an unknown, and therefore a more attractive option should a move be made.

In 40 1/3 innings for Indianapolis this year, the 27-year-old Mazzaro has a 2.01 ERA and a WHIP of 1.24. Still, the decision wouldn't be easy.

"There's never been, in my opinion, a bigger gap between Triple-A competition and the Major League competition," Hurdle said.

Worth noting

• The Pirates signed right-hander Matt Nevarez on Thursday, the Wichita Wingnuts announced. The 27-year-old had 23 saves and a 1.59 ERA for the Wingnuts of the American Association of Independent Professional Baseball. He was assigned to Double-A Altoona.

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