A.J. Ellis is back for his second year as the Dodgers’ starter, and hopes to be fully recovered from arthroscopic surgery on his left knee in October. Matt Treanor is gone after one year as the backup. The Dodgers will go in a different direction by giving rookie Tim Federowicz the first crack at the backup job – a small but notably different direction from recent years, when veterans like Treanor, Dioner Navarro, Brad Ausmus, Mike Lieberthal and Sandy Alomar held the role.

The four non-roster invitees in this group are an interesting collection of characters, some with checkered pasts. Can you say “Real World: Camelback Ranch”?

A.J. Ellis

The Dodgers couldn’t have expected much more from Ellis in his first year as a major-league starter: 133 games, a .270/.373/.414 slash line, 13 home runs and 52 RBIs. His on-base percentage led the team.

Dodger pitchers praised Ellis’ work ethic on the field and in pre-series meetings; his catcher’s ERA (3.33) was the second-best in baseball. Oh, and did we mention that Ellis acquired his superhuman strike zone awareness while on a spring training field trip to Alcor, where he was bitten by the radioactive dismembered head of Ted Williams? The perils of having a cult following …

The fly in the ointment was a lousy September/October stretch that saw Ellis hit .218. He’s the unquestioned starter, but will the Dodgers pace Ellis’ workload differently to keep him fresh later in the year? Ellis recently said he feels fine. We’ll find out for sure once Cactus League play begins.

Tim Federowicz

The Dodgers didn’t sign any free agent catchers this winter to major-league contracts, meaning the backup job is Federowicz’s to lose for the first time in his career. There are some experienced non-roster invitees in this group, but the Dodgers would prefer to start the season with Ellis and Federowicz as the tandem.

What can one expect from a backup catcher? Injuries often provide the answer to that question; Ellis avoided the disabled list in 2012 and Matt Treanor started 33 games. That wouldn’t be asking a lot of Federowicz, who batted .294/.371/.461 with 11 home runs at Triple-A Albuquerque last year.

But considering the 25-year-old has all of 20 major-league plate appearances in his career, he’s no sure thing. All four NRIs are more experienced. Would a bad spring jeopardize Federowicz’s chance of securing an opening-day roster spot? That is one of few major questions among the position players, with the Dodgers’ 25-man roster looking mostly set.

Ramon Castro (NRI)

In parts of 13 major-league seasons, never as a starter, Castro batted .237/.310/.424 for the Marlins, Mets and White Sox. After not playing last year, Castro could inherit the role Josh Bard (who has since retired) played at Albuquerque in 2012.

Castro, who turns 37 on March 1, did not have an uneventful 2012. He was arrested on Aug. 18 in Florida and charged with domestic violence and assault. Castro also served one year of probation in 2004 after pleading no contest to indecent assault.

Jesus Flores (NRI)

At 28 years old, and with 263 games of major-league experience, Flores is younger and more experienced than either Ellis or Federowicz. But he hasn’t been the same since shoulder surgery in 2009, batting .212/.249/.325 and throwing out 19.4 percent of attempted base stealers.

The Washington Nationals didn’t bring back Flores after he spent six years with the organization, and he’s in the Dodgers’ camp on a minor-league contract. He batted .262 with three home runs in 28 games for Magallanes in the Venezuelan Winter League. Should have a sizable chip on his shoulder, which is never a bad thing.

Wilkin Castillo (NRI)

Having caught nearly 400 Triple-A games over the last five years, with only a couple major-league cups of coffee, the 28-year-old Castillo will be playing for a job in Albuquerque. Castro, Flores and Alfonzo are the competition. Castillo hit .253/.273/.365 for the Rockies’ top affiliate in Colorado Springs in 2012.

Eliezer Alfonzo (NRI)

The most interesting question facing Alfonzo is if he can stay clean. He’s been suspended twice for using performance-enhancing substances – 50 games in April 2008 and 100 games in Sept. 2011. The latter suspension was dropped upon appeal for “nearly identical” reasons to those in the highly publicized Ryan Braun case.

For what it’s worth, Alfonzo batted .263 from 2006 to ’07, .181 from 2008 to ’10, and .267 in 2011 before he was suspended. He hit .361 over 39 games in the Mexican League last year.