Morkel, who had ankle surgery last year and spent five months on the sidelines, replaced Xavier Bartlett halfway through the first innings in Canberra on Thursday night.

But the 36-year-old conceded he had doubts coach Darren Lehmann would follow through with the pre-match plan to bring him in, having witnessed Bartlett make an immediate impact in the first over of the match.

The first-year BBL seamer Bartlett trapped dangerous Renegades batsman Shaun Marsh lbw and finished with 1-2 from his only over before making way for his new and vastly more experienced teammate.

Morkel repaid Lehmann's faith, claiming 1-29 from four overs and showing he can be a force in the coming weeks as the fifth-placed Heat push for a finals berth.

"I wasn't quite sure with Xavier bowling that beautiful first over, and with the guys going quite well, it was touch and go," Morkel said.

"But I was quite happy to get the call at the 10-over mark to get onto the field and bowl.

"You can only do so much bowling in the nets, you need to go out and perform in the middle and it's just nice to be out there."

Morkel is one of South Africa's greatest players of the modern era and sits fifth among the Proteas' all-time Test wicket-takers with 309 victims at 27.66.

But he admitted his comeback match, which doubled as his debut for the Heat, was somewhat "stressful".

That was despite there being no crowd at Manuka Oval for a match that was hastily rescheduled because of interstate travel restrictions.

"You're always going to feel pressure," Morkel said.

"For me, it's a new team and always as a newcomer when you come into a side you want to perform well and get going early on.

"I tried not to think about it and tapped into my experience a little bit."

The Heat hope to benefit from Morkel's presence on and off the field as he passes on his wisdom to the likes of Mark Steketee, Jack Wildermuth and Bartlett.

"I've been blown away by their professionalism," Morkel said.

"Xavier is going places, Stek is bowling fantastically well and Jack (is too).

"I felt disappointed for X (Bartlett) when he got subbed out tonight but it's about reading the conditions and for us we've got a bowling unit with a lot of options."

Morkel will feature again for the Heat when they take on Perth Scorchers in an important clash in Melbourne on Tuesday night.

Australian Associated Press