This year, January camp is a hybrid USMNT/U23 camp. This makes sense, as trying to assemble a separate full-sized, over-23 USMNT camp would be pretty pointless.
https://www.ussoccer.com/stories/2021/01/annual-january-camp-set-at-start-of-important-year-for-usmnt
* = Olympic eligible
^ = needs to file a one-time switch to play for the US
GK
Sean Johnson '89 (NYCFC)
Matt Turner '94 (New England)
*J.T. Marcinkowski '97 (San Jose)
*David Ochoa '01 (RSL)
*Brady Scott '99 (Austin)
Makes sense. Hamid is dropped, but mostly because Turner and Johnson were unavailable in December.
Marcinkowski is probably the Olympic front-runner because he's the only U23 GK who is actually starting. Ochoa may have a higher upside, though.
DF
RB/CB Tristan Blackmon '96 (LAFC)
CB Aaron Long '92 (NYRB)
CB Walker Zimmerman '93 (Nashville)
*RB Julian Araujo '01 (LA Galaxy)
*RB Aaron Herrera '97 (RSL)
*RB Bryan Reynolds '01 (Dallas)
*CB Aboubacar Keita '00 (Columbus)
*CB Henry Kessler '98 (New England)
*CB Mauricio Pineda '97 (Chicago)
*CB Miles Robinson '97 (Atlanta)
*LB George Bello '02 (Atlanta)
*LB Chris Gloster '00 (PSV Eindhoven reserves)
*LB Sam Vines '99 (Colorado)
We lose McKenzie from this group because of his impending sale to Genk. Farfan and Duncan (both Olympic eligible) are dropped after the December camp, perhaps because other players are available this time like Bello.
Anyway, I'm not sure if Reynolds will actually make it here depending on his own transfer saga. Araujo acquitted himself well in December.
At CB, I'd expect a Long-Zimmerman pairing. I'm interpreting the U23 callups to be the top domestic quartet in Kreis' eyes, with guys like Justen Glad perhaps slipping down the depth chart.
Blackmon is a player that Bob Bradley has liked at LAFC, who is a bit of a RB/CB tweener, but the USSF release describes him as a RB. Good solid player, not sure I see much of a NT future for him.
CM
Kellyn Acosta '95 (Colorado)
Sebastian Lletget '92 (LA Galaxy)
Cristian Roldan '95 (Seattle)
*Hassani Dotson '97 (Minnesota)
*Bryang Kayo '02 (Wolfsburg II)
*^Andres Perea '00 (Orlando)
*Tanner Tessmann '01 (Dallas)
*Eryk Williamson '97 (Portland)
*Jackson Yueill '97 (San Jose)
Williamson would definitely have been in camp in December if not for a minor injury after a strong season.
Berhalter seems to be particularly interested in Perea (who claims he'll make a decision about a one-time switch soon) and Bryang Kayo, who is a very physical box-to-box mid who is still in the reserves in Germany.
He's not going to be a USMNT contributor right away when the serious games start, but I'm excited about Tessmann's potential.
AM
Paul Arriola '95 (D.C. United)
Jordan Morris '94 (Seattle)
Chris Mueller '96 (Orlando)
*Cade Cowell '03 (San Jose)
*Jonathan Lewis '97 (Colorado)
*Djordje Mihailovic '98 (Montreal)
A solid enough crew, but our best wing options are abroad right now.
Cowell is a 17 year old who literally looks like he's 27. He's already a productive contributor off the bench in MLS and some people like him a lot. He's already established a good floor, but I'm not convinced about his touch and decision making yet.
Lewis' per-90 stats are always great, but year after year managers don't want to give him a consistent starting spot. It's not a great sign.
FW
Jozy Altidore '89 (Toronto)
*Daryl Dike '00 (Orlando)
*Jeremy Ebobisse '97 (Portland)
*Jesus Ferreira '00 (Dallas)
*Benji Michel '97 (Orlando)
Perhaps another chance to get a look at Daryl Dike after an injury knocked him out of the December camp. Ebobisse is a solid player too. Ferreira had a bad 2020 season and Michel looks like a useful MLS player but is fringy even at the YNT level. I think they are competing for bench places at Olympic qualifying.
Of note: Ayo Akinola will be in camp with Canada during this time as he weighs his options.