The skipper played the full match but handed over kicking responsibilities to full-back Elliot Daly and played “on one leg”, McCall said.
Farrell played down the significance of the injury, calling it a “little knock”.
Saracens made a bright start to the match but were soon usurped by the Premiership’s top team this season.
Lucio Cinti’s 78th-minute try had set-up a tense finish but the Men in Black ultimately fell just short reaching the final in Twickenham.
Farrell’s move to French side Racing 92 this summer coincides with the exits of Mako, Billy and Manu Vunipola and the retirements of Alex Lewington and Sean Maitland.
England lock and long-time Sarries teammate Maro Itoje called Mako and Billy Vunipola and Farrell “legends of the game”.
“They’re legends of England, they’re legends of Saracens, they’re some of the best rugby players to grace the pitch, one of the most successful trios to have played the game,” he said.
“It’s a shame we couldn’t finish it off the way we wanted to for them, but as a teammate watching them do their stuff over the past decade or so has been a pleasure and they have a strong legacy in the game.”
