Bulls rush their Bok discards back
The prop, Van der Merwe, is in the starting front row to face the Free State Cheetahs in Pretoria on Friday.
The midfielder, Serfontein, will play off the bench at Loftus Versfeld.
Marais also has in Francois Hougaard another Springbok discard back in the starting team, after the scrumhalf missed last week's win over Griquas due to personal reasons.
He replaces Ivan van Zyl who moves back to the bench.
Hougaard's return is the only change in the backline, but Marais made three changes in the pack.
Van der Merwe comes in for Werner Kruger, who is rested, and a fit-again Roelof Smit comes in for Jannes Kirsten at flank, with the latter moving to the bench.
In the other change up front Dean Greyling will be replaced Pierre Schoeman in the front row. Greyling has a knee strain and with Schoeman fit and ready to go following a long injury lay-off, Marais decided to give Greyling a break.
Under-21 regular Schoeman will make his debut in the competition, but has played for the Blue Bulls in the Vodacom Cup.
Serfontein comes in for Dan Kriel, who will return to the Under-21 team.
"Jan will certainly add some class to our backline," Marais said.
"He is in need of game time and there is no need to rush him back, so he will contribute off the bench," the coach added.
Blue Bulls captain Pieter Labuschagne is happy to have the Springboks back in the team.
"
Both Marcel and Jan were very unlucky to miss out on a World Cup spot, so we are very pleased that they are back to play for us," Labuschagne said.
"They will be keen to show why they should have been in the squad and that motivation will spur us on.
"The Cheetahs are dangerous and have their tails up, so we will need to be sharp on Friday."
* Meanwhile the Blue Bulls Company (Pty) Ltd confirmed earlier reports that Flip van der Merwe, another who missed the World Cup cut, has been released to join French club Clermont.
Van der Merwe, 30, was only scheduled to join the Top 14 outfit, Clermont, after the completion of the Currie Cup season.
However, after the 36-Test veteran – who was in the Boks' wider training squad – failed to make the World Cup cut he was released to move to France immediately.
Blue Bulls: 15 Warrick Gelant, 14 Travis Ismaiel, 13 Dries Swanepoel, 12 Burger Odendaal, 11 Jamba Ulengo, 10 Tian Schoeman, 9 Francois Hougaard, 8 Arno Botha, 7 Roelof Smit, 6 Pieter Labuschagne (captain), 5 Marvin Orie, 4 Jacques du Plessis, 3 Marcel van der Merwe, 2 Bandise Maku, 1 Pierre Schoeman.
Replacements: 16 Jaco Visagie, 17 Dayan van der Westhuizen, 18 Rudolph Snyman, 19 Jannes Kirsten, 20 Ivan van Zyl, 21 Louis Fouche, 22 Jan Serfontein.
Date: Friday, September 4
Venue: Loftus Versfeld, Pretoria
Kick-off: 19.19 (17.10 GMT)
Referee: Rasta Rasivhenge
Assistant referees: Francois Pretorius, Vusi Msibi
TMO: Willie Vos
