Serena Williams’ vague Instagram comment under Carlos Alcaraz’s training post has set off fresh speculation about a mixed doubles team-up at the 2026 US Open. The 44-year-old legend, returning to competition after a four-year hiatus, wrote *“They not ready”* under Alcaraz’s recent rehab photos—sparking fan theories that she’s signaling a partnership with the 23-year-old Spaniard.

What did Serena Williams say—and why does it matter? Williams’ comment came after Alcaraz posted training images from his center in Spain, where he’s rehabbing a wrist injury that has sidelined him since early June. Her cryptic reply, combined with her recent return to doubles at Wimbledon (where a knee injury derailed her plans to team with Venus), has fans convinced she’s dropping hints about Flushing Meadows.

How did fans react to the speculation? Tennis journalist **José Morgado** was quick to interpret the post as a tease: *“Serena Williams clearly teasing a US Open mixed doubles partnership with Carlos Alcaraz,”* he wrote on X. Others piled on, with one fan declaring, *“Yeah, I’m almost certain they’re playing mixed at US Open.”* Doubters, however, argue Williams may simply be referencing her own doubles chances—she’s a three-time US Open champion in doubles (two in women’s, one in mixed).

What’s Carlos Alcaraz’s current status ahead of New York? The seven-time Grand Slam champion remains absent from the Canadian Open draw, though he could make his ATP Tour return in Cincinnati before his title defense. His mixed doubles debut at the 2025 US Open with Emma Raducanu ended in a first-round exit, but a partnership with Williams—if confirmed—would carry far more weight. Venus Williams, meanwhile, has been linked to Jannik Sinner in similar rumors.

When could this partnership be announced—and what’s next? No official confirmation exists, but Williams has hinted at competing in the North American hardcourt swing. Alcaraz’s return timeline remains uncertain, though his Instagram activity suggests progress. If the pair do team up, it would mark a high-profile revival for mixed doubles—a format Williams dominated in her prime.