“We think it’s a good message for our current female players and future players,” Adams said. “It’s O.K. to go out and be a woman and become a mother and then come back to your job, and I think that’s a bigger message.”

But some disagree. Barbora Strycova of the Czech Republic, who is ranked No. 24, said a woman returning from pregnancy did not deserve special treatment.

“Why should we give someone who chooses to have a baby seedings?” Strycova said at a tournament in Birmingham, England. “It’s not when you are injured. I think you shouldn’t get seedings. It’s tough, but this is my opinion.”

When a player outside the rankings is granted a seed, it not only hurts the No. 32 player — who would theoretically be pushed out of the seedings — but also could force the No. 8 and No. 16 players to be bumped from those coveted slots, too.

Still, most players say they agree with the U.S.T.A.’s decision. The world No. 1, Simona Halep, has endorsed the idea of granting Williams a seed. So has Petra Kvitova, who is ranked No. 8. But when asked on Thursday in Birmingham to pick a slot for Williams, Kvitova paused and said, “No. 9.”

The WTA does offer ranking protection to help players get into tournaments. Williams, who has six U.S. Open titles, was ranked No. 1 at the time she stopped playing, after winning the Australian Open in January 2017. Her ranking fell to No. 491 because of inactivity, but she is able to use a protected ranking to enter up to eight tournaments a year. She can also be invited to participate through wild cards, which are given out by individual tournaments.

Williams, 36, endured severe complications during labor and has not yet reached peak fitness and precision on the court. She has played three tournaments since returning to tour in March. But she had to drop out of the French Open with a pectoral injury after she won her first three matches there, two of them against seeded players (No. 17 Ash Barty in the second round and No. 11 Julia Görges in the third).