SANTA CLARA, Calif. -- On Halloween, it will be exactly three years since the San Francisco 49ers traded a second-round pick to the New England Patriots for quarterback Jimmy Garoppolo.

Since arriving in the Bay Area, Garoppolo has started 28 of a possible 46 regular season games. He guided the 49ers to a Super Bowl, but couldn't deliver the Lombardi trophy. On Sunday he returns to Foxborough, Massachusetts, for the first time since the trade with plenty of unanswered questions about his overall ceiling.

And while Garappolo's return makes for an intriguing storyline as the 3-3 Niners and 2-3 Patriots (4:25 p.m. ET, CBS) meet in a game both teams need to win, it hasn't exactly jumpstarted a nostalgic walk down memory lane for either Garoppolo or Patriots coach Bill Belichick.

"It will be cool," Garoppolo said. "You know, getting back to the old stomping grounds. ... Going to be another dog fight."

For his part, Belichick was his usual, understated self when asked multiple questions about Garoppolo on Monday. He said the trade happened "a long time ago" and that the Patriots have "moved on from that." When asked about keeping in touch with Garoppolo since his departure, Belichick said he prefers to keep his conversations with current and former players between he and the individual.

"I'm glad that it's worked out for him in San Francisco," Belichick said. "I hope it doesn't work out on Sunday. But otherwise, happy that he had the opportunity to play for a great coach, and a great organization, and play on a great team. I think he deserves that. He certainly worked hard and earned it."

Despite Belichick's happiness for him, an argument could be made Garoppolo is one of the most polarizing quarterbacks in the league when it comes to the opinions of outside observers.

Much of that can be attributed to a series of career stops and starts most quarterbacks don't experience. The combination of Tom Brady's presence in New England and a variety of injuries has made it hard for Garoppolo to put together a complete picture that allows for a deeper analysis of what kind of quarterback he is and could still become.

He didn't start the first three games after the trade to the 49ers, missed 13 games in 2018 with a torn ACL and two games this season with a high right ankle sprain.

"The more things you go through with a player, the more situations, the different types of years you go through with someone, the more you grow and the more you learn," coach Kyle Shanahan said. "It's almost like we've been with each other for four seasons, but it almost feels like kind of just one, one full one. You always want more time with that."

Garoppolo's 2020 season has raised as many questions as it has answered. He's started four games, but the two he didn't finish best illustrate the varied takes on where he stands.

In Week 2, Garoppolo battled through the ankle injury to put together his best half of the season, finishing with a QBR of 99.6 before his day ended early. After missing the next two games, Garoppolo returned in Week 5 and had a miserable outing against the Miami Dolphins on the balky ankle. He posted a career-low 1.6 QBR and was benched at halftime.

Beyond staying healthy, Garoppolo must prove he can take the offense to the next level. He's proved capable of handling many of the short and intermediate throws Shanahan has drawn up but the Niners have largely lacked a downfield passing component.

Last year, Garoppolo led the league in completion percentage on passes thrown 20-plus yards in the air (65.5) but he was also 29th among all quarterbacks in attempts with 29. This year, Garoppolo is 0-for-8 on such throws with two interceptions and his average air yards per attempt is 6.41, tied for third fewest among starting quarterbacks.

No matter how creative Shanahan and his staff are, when a defense can sit on the shorter stuff and the running game, it makes it tough to move the ball consistently.

"They can only screen you and quick game you for so long," ESPN NFL analyst Dan Orlovsky said. "Eventually, you are able to clamp down on them. With the 49ers, you're only going to be able to win so many games throwing the ball 2 yards past the line of scrimmage. You might be able to win some games and Kyle is phenomenal but when it comes to it, you have to be able to penalize teams for playing a certain way. Peyton Manning used to always say that in our meetings. ... Jimmy has got to get to that point with San Francisco. When teams start clamping down you have to hurt them or they won't care."

After this season, Garoppolo has two years remaining on his contract with cap hits of $26.9 million in 2021 and $27 million in 2022. Those are reasonable numbers for a starting quarterback but the Niners could, theoretically, get out of Garoppolo's contract this offseason with $2.8 million in dead money and save $24.1 million in the process.

It's hard to imagine that scenario playing out given Garoppolo's regular season and playoff run for the Niners in 2019. He's provided his share of bright spots and is beloved in the locker room. The more likely scenario is that he's the 49ers quarterback at least through this contract and possibly beyond.

Still, three years after the trade, the questions persist. That Garoppolo remains unfazed might be his greatest strength and the one question to which he's delivered a definitive answer.

"When you are having people on you like that and you come in to work on Monday and then you go into the huddle on Wednesday in practice and guys can hear it in your voice how you call a play, kind of how you walk around," Shanahan said. "He walks confident and tall each day. He doesn't have the demeanor of a guy who's worried about much. ... When Jimmy's in there, you can tell the team believes. That's one of the most important things with giving us a chance to win."