Major league rosters can expand Thursday, the same day the Arizona Fall League rosters will be announced.

Will Yoan Moncada’s name be included on both rosters?

One reason the Boston Red Sox may send Yoan Moncada to the Arizona Fall League would be to work on his fielding. Moncada is still learning to play third base – a position where Boston needs help. Sunday was only his eighth game at the position with the Portland Sea Dogs. Shawn Patrick Ouellette/Staff Photographer

Earlier this month, Red Sox Manager John Farrell hinted that Moncada, now playing third base for the Portland Sea Dogs, would go to the Arizona Fall League to continue to adjust to his new position.

But on Sunday, Farrell wouldn’t rule out Moncada being called up to the majors, saying the decision “has yet to be determined.”

Could Moncada go to the majors and then head to the AFL? Sure. Mike Trout did that in 2011, jumping from Double-A to the Angels, then moving to the AFL after the season. By the way, the AFL’s Scottsdale Scorpions were loaded that year with Trout, Bryce Harper and Will Middlebrooks (and Arnie Beyeler as manager).

Moncada, 21, is Boston’s top prospect but still needs time to develop. But his production in 43 Double-A games is intriguing: a .286 batting average, .941 OPS and 11 home runs.

Boston isn’t getting a lot of production at third base from Travis Shaw (.175/.610 in the second half) and Aaron Hill (.195/.512 since his trade to Boston).

Moncada has been dominant when batting left-handed (.313/1.003), not so much right-handed (.171/.710). He has power right-handed – like his home run on a fastball Sunday. But he also struck out twice in the game, looking at a slider and swinging at a change-up.

Moncada shows a lot of athletic talent at third base but Sunday was only his eighth time at the position. He can steal bases (93 of 108 in his career), but is still learning the nuances of the running game, especially at higher levels.

Here’s one scenario: Moncada is promoted to Boston late Wednesday night. Boston is off Thursday and opens a long trip Friday at Oakland.

The Red Sox like their touted prospects making debuts far away from the glare of Boston. For example, Xander Bogaerts played his first game in San Francisco in 2013 and Andrew Benintendi debuted in Seattle earlier this month.

If Moncada is promoted by Wednesday, he becomes automatically eligible for the postseason roster should Boston make the playoffs.

THE ARIZONA FALL LEAGUE has been called the graduate school for prospects. Running from Oct. 8 to Nov. 19, it’s intended to be a showcase for some of the game’s best prospects, most coming from Double-A, with some from Triple-A and an occasional Class A player. Some of the prospects may not be big names but are promising players who need more work – especially those who missed time because of injury or have moved to a new position.

Each of the six AFL teams contains prospects from five major league teams, with minor league coaches assigned to each team.

Sea Dogs Manager Carlos Febles will manage the Surprise Saguaros.

The Red Sox players chosen for the Surprise team will be announced Thursday.

AFL CANDIDATES from the Red Sox, besides Moncada, include some other standouts in Portland.

Shortstop Mauricio Dubon would be a good candidate. Not only did Dubon tear up Double-A pitching (.342/.923) but excelled at shortstop. Dubon, 22, is likely to be introduced to other positions soon, maybe in Arizona.

Dubon has played second and third before, and probably could handle the outfield.

With Dubon blocked at so many positions in Boston, the Red Sox may want to find a way to get his quick bat to the majors. Think of him as a right-handed Brock Holt.

Catcher Jake Romanski, 25, is having a breakout year in Portland (.298/.724). He’s superb at throwing out runners but the Red Sox would like to see improvement in his overall defense. He caught 83 games in Portland and could catch a few more in the fall.

Outfielder Aneury Tavarez, 24, came out of nowhere this season, batting .331/.873. In 67 games with Portland last year, he batted .226/.616. It would be good to see Tavarez against better competition.

One pitcher seems an obvious choice. Right-hander Michael Kopech missed the first half of the season with a broken hand. In 10 starts with Salem he’s 4-1 with a 1.23 ERA and 81 strikeouts in 51 innings. Kopech can rely solely on his 100 mph fastball in Class A. Boston needs to see him face more advanced hitters.

Portland could offer several pitchers to the AFL for more work. Ben Taylor and Ty Buttrey converted to the bullpen this year, and starter Kevin McAvoy missed time with injury. Left-handed relievers Luis Ysla and Williams Jerez are other candidates.

IN PAWTUCKET, left-hander Roenis Elias (10-5, 3.78 ERA) allowed three hits in six innings of shutout ball (three walks and six strikeouts) Sunday.

Trouble is, Elias didn’t look nearly as good during his short stint with Boston (three games, 72/3 innings, 11 earned runs).

Rusney Castillo went 3 for 5 on Sunday with a double and triple. In 22 games in August, Castillo is batting .365/.944.

IN SALEM, third baseman Rafael Devers (.335/.944) and outfielder Danny Mars (.331/.844) have been excellent in the second half of the season. They will be in Portland next year, as will first baseman Nick Longhi, who has been consistent all year (.280/.736).

IN GREENVILLE, 18-year-old wonder Raniel Raudes (11-5, 3.63 ERA) pitched only three innings in his start Sunday, allowing one hit. Raudes, in his first full pro season, is already up to 1112/3 innings and the Red Sox are cutting back his workload in the final week of the season.

IN LOWELL, two high draft picks from June are shining. Third baseman Bobby Dalbec (fourth round, Arizona) is batting .374/1.119 in 28 games. Shortstop C.J. Chatham (second round, Florida Atlantic), is batting .275 in the last 10 games, but is also showing his promising power, with three home runs in his last three games.

IN THE GULF Coast League, first-round draft pick Jason Groome made his second start last week: two innings, two hits, one run, no walks and five strikeouts. Groome gave up a leadoff single. The runner stole second, advanced to third on a single and stole home.

A SCOUT WITH another organization visited Hadlock Field last week and the subject of Mookie Betts’ success came up. The scout was not surprised. “I have rated only four prospects (with top marks) – Mike Trout, Bryce Harper, Mookie Betts and …

“Andrew Benintendi.”

NOTES: Former Sea Dogs and Red Sox reliever Daniel Bard is pitching for the first time in two years. Signed by the Cardinals, Bard, 31, was activated this month in the advanced Class A Florida State League. In five games (only 11/3 innings), he has allowed eight earned runs on two hits, eight walks and five hit batters, with no strikeouts … Former Sea Dogs outfielder Shannon Wilkerson recently was released by the Twins organization. Wilkerson, 28, was batting .241/.628 in Double-A.