Golden State Valkyries fans had to endure a slew of bad news yesterday. The team waived Kate Martin , and Iliana Rupert will have to miss the season due to pregnancy. The Valkyries filed for a replacement contract for the latter, and they desperately need it. With Rupert out, their big rotation currently consists of Kiah Stokes and Laeticia Amihere. That’s not enough to survive injuries or even foul trouble, or to compete with the top teams in the W.  Even if the replacement contract is granted by the league, the Valkyries face another big problem: There aren’t many centers available right now, who promise to be as impactful as Rupert would have been.  Chloe Bibby and Nikolina Milic were waived by the Phoenix Mercury and Toronto Tempo, respectively. Both are solid backups, but neither is likely to recover the potential the Valkyries lost with Rupert. Kalani Brown and Teaira McCowan offer great size, but they don’t provide any of the versatility Rupert does.…