NFL free agency: Mitchell Trubisky signs with Bills as Josh Allen insurance; 49ers now may turn to Joe Flacco as backup to Jimmy Garoppolo

Buffalo Bills quarterback and MVP candidate Josh Allen -- +1400 at William Hill Sportsbook to win the 2021 MVP -- hasn't missed a game in the past two seasons, but the Super Bowl 56 contenders have ensured they have a quality backup in case Allen does miss time in 2021 by signing former Chicago Bears starting quarterback and ex-No. 2 overall pick Mitchell Trubisky to a one-year deal. That is a big loss for the San Francisco 49ers as they were eying Trubisky as well but now could turn to 36-year-old Joe Flacco.

While Trubisky largely flopped in Chicago, which traded up in the 2017 draft to take him over Patrick Mahomes and Deshaun Watson, he's still only 26 (27 in August), was 29-21 as a starter and certainly is a backup upgrade in Buffalo over the likes of Matt Barkley and Jake Fromm. Barkley is a free agent and Fromm, a 2020 fifth-round pick out of Georgia, has yet to take an NFL snap and likely will serve as the No. 3 this year.

Just for a point of reference, over the past three seasons Trubisky was 25-10 with Chicago with an 89.9 QB rating, yet the Bears let him walk and just signed Andy Dalton as the presumed 2021 starter. Over the past three seasons, he is 11-22 with an 84.1 QB rating. Oh, and Dalton is seven years older. Chicago doesn't play Buffalo this season.

The big losers in Trubisky to the Bills, though, are the 49ers. GM John Lynch is on record wanting to upgrade at the backup spot behind Jimmy Garoppolo because Jimmy G is so injury-prone. Trubisky appeared to be a good fit in Kyle Shanahan's offense as someone who knows how to use his legs and make plays outside of the pocket.

Chicago traded up from the No. 3 pick in the 2017 draft to No. 2 with the Niners to take Trubisky. San Francisco did no better with that third pick in selecting Stanford defensive tackle Solomon Thomas, who is long gone.

With guys like Trubisky, Dalton, Jacoby Brissett, Tyrod Taylor and Ryan Fitzpatrick off the market, the Niners may be forced to turn to Flacco as Jimmy G insurance. The team is hosting him for a visit. Yes, Flacco is experienced and a former Super Bowl MVP (beat the 49ers), but he has been horrible and injury-prone the past two seasons, going 2-10 (5-7 against the spread) as a starter with the Jets and Broncos. Flacco played under 49ers quarterbacks coach Rich Scangarello in his lone season with Denver.

Probably the biggest-name other free-agent QB on the market is Alex Smith, who of course was the No. 1 overall pick in the 2005 draft by the Niners. Smith has been linked to Jacksonville, which would then make Gardner Minshew available. Don't rule out the 49ers trading for Minshew if they don't sign Flacco. San Francisco also is heavy in the Deshaun Watson sweepstakes, and Watson has indicated he would like to play for the 49ers.

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