Lions head coach Warren Gatland is set to name his 36-man squad on May 6 - and Biggar is timing his charge perfectly.
The 31-year-old was man of the match for Saints last weekend, delivering an all-action display in the 23-18 Gallagher Premiership win against Leicester Tigers.
Biggar battled through injury in the closing stages to make some hugely important tackles that helped to preserve his team's lead.
And he had also had a big impact for Wales this year, steering his country to Six Nations glory.
Boyd is a big fan of Biggar, and has been even since the pair teamed up at Saints in 2018.
And the black, green and gold boss has backed his fly-half to not only go on the Lions tour this summer, but to have a real say against the Springboks.
Boyd said: "I would certainly be picking him to go to South Africa.
"I had two years with the Sharks out there and I know it pretty well.
"In Super Rugby we played the South Africans on a regular basis and Dan Biggar is very suited to playing in South Africa.
"I've had no correspondence with any of those (Lions) people but I would certainly expect him to be named in that side."