The phrase "as a frontrunner to" is correct and usable in written English.
It can be used when discussing someone or something that is leading or has a strong chance of success in a competition or situation.
Example: "The company is seen as a frontrunner to win the prestigious award this year."
Alternatives: "leading candidate for" or "top contender for".
And Sir Hugh, seen as a frontrunner to be the next permanent Scotland Yard chief, has been vocal in his criticism, suggesting politicians were irrelevant to the process.
The day after his menswear show in Paris, his name was being mooted as a frontrunner to take over at Burberry or Louis Vuitton.
There is nothing left for us". Nouri al-Maliki, Iraq's incumbent prime minister, is being hailed by Iraqi commentators as a frontrunner to win a third term.
One of Britain's most outspoken architects has emerged as a frontrunner to become London's "design tsar" promising more landmark buildings and attacking the current lack of "coherent vision".
A 56-year-old conservative cleric relatively unknown to the outside world is quietly emerging as a frontrunner to be Iran's next supreme leader.
It is a mark of Tranter's success that she was immediately installed as a frontrunner to succeed Ms Heggessey when she quit BBC1.
The former president's son, Ferdinand Marcos Jr, generally known as "Bongbong", is a frontrunner to become vice-president in the national elections on 9 May.
Ms Sturgeon is seen as a clear frontrunner to replace him.
The Bookseller's diarist Horace Bent immediately put forth Advanced Pavement Research as a frontrunner, pointing to its "echoes of winners past", such as Highlights in the History of Concrete, which took the prize in 1994, and Designing High-Performance Stiffened Structures, which won in 2000.
Scrambling to divert the media's attention from the question of when, exactly, Romney's tenure at Bain Capital really ended, as compared to when he says it did, they decided to leak the shiniest object of them all: a veepstakes rumor about a "surprising name" emerging as a frontrunner, floated directly to Matt Drudge.
Schieffer accused Cain, a cancer survivor himself, of glorifying smoking and argued that as a frontrunner he needed to begin taking more responsibility for raising the level of dialogue.
