More notes from Thursday's workout (and Berken update)

SARASOTA, Fla. - Reliever Jim Johnson threw off a half mound today and will progress to a regular mound on Saturday. Johnson has been receiving treatment for tightness in his lower back, but he appears to be fine. "Everything's good," he said. "I'll be on a full mound Saturday. Riveting stuff." I can appreciate good sarcasm. Zach Britton threw on flat ground again today. "Neither one of them is behind. That's for sure," manager Buck Showalter said of Johnson and Britton. "If anything, it's borderline the other way." Still no sign of catcher Ronny Paulino and pitcher Dennys Reyes, who haven't solved their visa issues. They're expected in camp at some point. Nobody has seen outfielder Endy Chavez, who's due today, but Showalter downplayed his absence by saying, "I think he's got a chance to make the club." Chavez might have reported while Showalter was on the field. He'll be in the clubhouse Friday morning. I mentioned earlier that Brian Roberts will take the field with his teammates for Friday's first full-squad workout. That doesn't mean he's full-go, but he'll be out there. Showalter spoke to Roberts on the field before meeting with reporters. "I think I've got a pretty good idea how the day's going to go tomorrow, but let's see what happens between now and tomorrow," Showalter said. "He's going through a lot. It's been a tough road for him. He played 150 games a year for an extended period of time. Nobody loves the game of baseball more than Brian Roberts, and nobody probably loves the Orioles more than Brian. I think sometimes we really underestimate his level of frustration with this in the past. "I know we've made some progress and that's been very encouraging, but I don't think anybody's got a definitive timeline on him. We all know what it would mean to get him back, but what are you going to do if he's not able to? I think it's prudent on our part to prepare both ways, and we have. It's a lot easier to write a lineup, but for every one that I've written with him, there's three or four I've written without." When it comes to choosing a utility player for the 25-man roster, Showalter said the tie-breaker might be the candidate's ability to play the outfield. Shortstop skills also are important. The following pitchers had bullpen sessions today: Jason Hammel, Kevin Gregg and Luis Ayala in Group 1, Jake Arrieta, Tommy Hunter and Tsuyoshi Wada in Group 2, Matt Lindstrom, Darren O'Day and Dana Eveland in Group 3, Brad Bergesen, Alfredo Simon and Pedro Strop in Group 4, and Zach Phillips and Troy Patton in Group 5. Strop was really bringing the heat, and he kept hitting his target. He looked very good. Arrieta's right elbow appears to be fine. Good velocity, good command. "So far, so good," Showalter said. "He's doing great so far." Showalter was told that Arrieta threw two innings in an alumni game in Fort Worth before reporting to camp. Single-A Delmarva's Michael Ohlman caught Arrieta today. As soon as the session ended, Chris Hoiles walked over to Ohlman and quickly offered him some tips. And finally, the Dodgers claimed former Orioles outfielder Matt Angle off waivers. The Orioles would have outrighted him to Triple-A Norfolk if he cleared. The Blue Jays claimed pitcher Rick VandenHurk earlier this week. UPDATE: The Orioles are listing reliever Jason Berken as day-to-day after he tweaked his left hamstring during conditioning drills today. Berken threw a bullpen session on Wednesday. The good news is the injury isn't serious enough to warrant immediate concern, but we'll know more tomorrow when Berken shows up at camp. He's fighting for a roster spot, so any setback is an issue.