The only game Williams has not started in the Tandy era was the 73-0 hammering inflicted by South Africa in November 2025.
That match fell outside World Rugby’s international window with England-based club players not eligible for the fixture.
In those 12 internationals Williams has started, Tandy has used the replacement scrum-half for just 48 minutes with an average of four minutes per game.
Williams has playing a full 80 minutes on five occasions with his average minutes per Test at 74.3 minutes, although that includes two yellow cards he has picked up.
The players chosen as bench cover for Williams have played a combined total of only 30 minutes in the past nine Tests in 2026 with Williams starting all the games and completing four of them.
“There is a massive reliance on Tomos, you can’t run away from that,” said Tandy.
“Most teams are reliant on big players and Tomos loves playing. If you look at getting a rhythm, Tomos loves playing rugby.
“Being taken off, not that it is an issue, but at Saracens, it’s probably more of a rotation policy.
“Some boys like being in the groove, while some can handle that rotation policy. But at the minute, he’s in a great space.”
Kieran Hardy had been Williams’ under-utilised deputy until he picked up a serious knee injury in October that could rule him out of the 2027 World Cup in Australia.
Morgan-Williams and uncapped Dragons scrum-half Che Hope are the other scrum-halves in the autumn squad.
“Reuben is doing well and Che is an exciting young talent,” said Tandy.
“It’s just making sure we feel we manage that bit correctly so we are doing it right for that person, as well as Tomos.
“There is no substitute for Test rugby, but you’ve also got to do right by them, with who you’re playing against.
“So potentially putting Che in to start against New Zealand, those are the things we, as coaches, take into consideration. We know we need to grow that space.”