BOSTON — Baseball America ranks 20-year-old shortstop Franklin Arias the No. 2 prospect in the Red Sox system and No. 49 on its Top 100 list.
The Athletic’s Keith Law, meanwhile, ranks Arias the No. 12 overall prospect in baseball.
There are some concerns with his game though, including whether he can hit for enough extra-base power. His range and arm are both above-average. He’s known for strong bat-to-ball skills and has batted .299 with a .377 on-base percentage in 240 minor league games.
But he needs to slug more. He finished 2025 with a .388 slugging percentage, eight homers, 27 doubles and one triple in 116 games between Low-A Salem, High-A Greenville and Double-A Portland. He also has a rather high 47.7% ground ball rate in pro ball.
The Red Sox have wanted Arias to focus on two areas and he is addressing both:
~ Hitting the ball in the air more consistently and get to his point of contact a bit further out in front is important.
~ They also asked him to put on weight and he’s done it this offseason. The 5-foot-11 shortstop was 170 pounds last season. He said at the Red Sox Rookie Development Camp in January that he’s now 179 pounds, something he has achieved through nutrition and work in the weight room.
“That (point of contact more out in front) is one of the things I want to keep improving,” Arias said through translator Carlos Villoria Benítez. “I’ve talked to them during the season and the offseason to try to improve that point of contact to put the ball in the air. I feel that’s going to be one of my main focuses in spring training.”
Then-Greenville hitting coach JP Fasone, who now serves as the organization’s minor league hitting coordinator, explained in June: “He’s really good at letting the ball travel and taking his hits. But I think there’s more opportunities for him to kind of catch the ball out in front, hit the ball in the air a little bit more and pull it a little bit more. He tends to miss some pitches early in the count. I think as he continues to improve those pitches will get hit.”
So far, Arias’ swing adjustments haven’t been drastic, he said. He called them more “tweaks.” His slugging percentage did drop from .446 in the first half to .331 in the second half last year. However, he showed some impact in 10 games at Portland to close out the year with two homers, two doubles and a .435 slugging percentage.
The right-handed hitter has to improve against left-handed pitchers. He has hit better and slugged more against righties. He posted a .291/.343/.412/.755 line in 399 plate appearances vs. righties and a .235/.307/.313/.620 in 127 plate appearances vs. lefties in 2025.
“I was able to see making those changes will lead to better results in terms of slugging,” Arias said.
Boston’s newest prospect
The Red Sox received Gage Ziehl, a mid-level pitching prospect, in their trade that sent reliever Jordan Hicks and prospect David Sandlin to the White Sox on Sunday.
The 22-year-old righty posted a 4.12 ERA, 1.26 WHIP, 90 strikeouts and 19 walks in 22 outings (21 starts) between Low-A, High-A and Double-A in 2025. Opponents batted .274 against him.
Baseball America grades his sweeper 55 (above average) on its 20-80 grading scale. It grades his cutter 50 (major league average), both his curveball and changeup 45 (fringe average) and his fastball 40 (below average).
His BA scouting report notes, “Even though he commands his fastball well and tweaked it to generate a bit more cut in 2025, Ziehl used his below-average 92 mph four-seamer just 13% of the time. His maxed out 223-pound frame suggests it’s unlikely more velocity is on the way. Instead, Ziehl relies on his mid-80s sweeper and 89 mph cutter, throwing those two pitches nearly 70% of the time with near-even distribution. His sweeper has above-average spin rates and is his best swing-and-miss offering. He rounds out his arsenal with a fringy upper-80s changeup that needs more separation from his fastball and a downer 80 mph curveball that he throws the least but generated his highest miss rate in 2025.”
Impactful minor league signing?
MassLive’s Sean McAdam wrote a column last Friday, listing 15 questions entering spring training. His third question: Will the Red Sox look to upgrade the back-up catching spot?
The next day, the Red Sox signed catcher Matt Thaiss to a minor league deal with an invite to big-league camp.
The 30-year-old Thaiss has appeared in 305 major league games and should compete with Connor Wong to be Carlos Narváez’s backup. He’s a terrific blocker but struggles with arm strength and framing. That said, arm strength was a concern with Narváez entering camp last year and the Red Sox significantly improved it by involving the pitching department.
Thaiss bats left-handed while Narváez and Wong are both right-handed hitters.
Interesting to note, the Red Sox drafted Thaiss in the 32nd round in 2013 out of Jackson Memorial High in Jackson, New Jersey, but he did not sign. He kept his commitment to Virginia and was an Angels’ first-round pick three years later.
Minor league non-roster spring training invitees
Spring training begins Tuesday. The following are the minor league non-roster invitees by position:
Right-handed pitchers: Osvaldo Berrios, Tayron Guerrero, Hobie Harris, Seth Martinez, Vinny Nittoli, Wyatt Olds, Noah Song, Devin Sweet, Jacob Webb.
Left-handed pitchers: Alec Gamboa, T.J. Sikkema, Jeremy Wu-Yelland.
Catchers: Nate Baez, Jason Delay, Nathan Hickey, Ronald Rosario, Matt Thaiss.
Infielders: Vinny Capra, Max Ferguson, Mikey Romero,
Outfielders: Allan Castro, Tyler McDonough, Braiden Ward.
