(Photo credit: Eakin Howard-Imagn Images)

Postseason positioning will be at stake Friday night when the fifth-place Phoenix Mercury, playing the second leg of a back-to-back, host the seventh-place Golden State Valkyries.

The matchup will be the second this week between the WNBA playoff hopefuls, and the second straight against Phoenix for Golden State. Kahleah Copper's 25 points led the Mercury in a 98-91 win in San Francisco on Tuesday, Phoenix's third victory in as many meetings with the first-year Valkyries.

Copper suffered a rib injury on Thursday against Las Vegas, however, as she tried to move around a screen with at the 6:24 mark of the third quarter of the 83-61 loss by Phoenix (21-14).

Alyssa Thomas, who posted a double-double of 17 points and 11 rebounds, and Satou Sabally (15 points) were the only Phoenix scorers in double figures. The 61 points were the Mercury's fewest in any game this season, and a stark contrast to their 98 points against a typically stout Golden State defense on Tuesday.

The Valkyries (18-17) are tied with the Atlanta Dream for the second-fewest points allowed per game in the WNBA at an average of 77.4.

The back-to-back losses have left Golden State just a half-game ahead of the eighth-place Seattle Storm and a game up on the first team out of the playoff picture -- the Los Angeles Sparks -- heading into Friday's slate. Phoenix, meanwhile, remains a half-game behind th New York Liberty for fourth place and the last seed with home-court advantage.

Golden State is pursuing a postseason berth in its expansion season, even with a depleted roster. The Valkyries lost Kayla Thornton, who led the team in scoring (14 points per game) and rebounds (7 per game) last month following her season-ending knee surgery.

The Valkyries were further short-handed on Tuesday with Cecilia Zandalasini (11.2 ppg) out with a left calf injury and Tiffany Hayes (11.9) on scheduled rest.

'There's an element of difficulty from a standpoint of getting fatigued or playing through foul trouble,' guard Veronica Burton said following the loss on Tuesday.

Burton, who finished with 24 points and 14 assists against the Mercury, also noted Golden State's height disparity with 6-foot-4 center Iliana Rupert also out in the most recent contest. Rupert sat due to concussion protocols after being hit in the head during last Sunday's 79-63 loss at Atlanta.

It was not clear whether Rupert would be available on Friday.

Lamenting Phoenix's injury woes with the loss of Copper, the Mercury's Sabally pointed to other late-season injuries around the league during this home stretch as an issue for the league.

'It's part of the game, but the amount of players going down this season is also really sad,' Sabally said in her postgame press conference. 'At some point, we should really look at that.'

--Field Level Media