GLENDALE, Ariz. (AP) — Los Angeles Dodgers ace Clayton Kershaw threw his first bullpen since Feb. 20, an all-fastball session of 20 pitches.The three-time NL Cy Young Award winner has been slowed by left shoulder discomfort."Good day, good step forward, for sure, and just kind of keep going forward from here," Kershaw said after throwing to catcher Russell Martin. "Felt great. It was another good day. I'll take that right now, just keep moving forward from here and start building up."Los Angeles is not sure whether Kershaw will be available for its March 28 opener against Arizona. Dodgers president of baseball operations Andrew Friedman said Kershaw showed command and "the feel for what he was doing with the ball was very Kershaw-esque.""It looked really good, he felt really good," Friedman said. "He executed extremely well. For this step in the progression, it was everything we could have hoped for. "Kershaw will throw another bullpen and start throwing off-speed pitches soon. He has made eight consecutive opening-day starts but has mixed feelings about the importance of pitching this year's opener."Yes, because I have a little streak going and just the history behind it, it is pretty cool," he said. "But no, in the fact that it's not worth — it's one game out of, you know, you've got to kind of weigh that back and forth."After stretching and playing catch, including long toss, the 30-year-old Kershaw jogged over to the bullpen, conversed briefly with Martin and threw three pitches while Martin stood.Kershaw then went into full windups as Martin crouched, and 18 of 20 fastballs were exactly to the spot Martin placed his mitt.Afterward, Kershaw disappeared into the clubhouse for a few minutes then emerged to greet several family members, including his young daughter, Cali Ann, who ran into his arms. He picked her up with a huge smile on his face.NOTES: After limited activity for one week because of a lower back strain, Martin is beginning his second week working back to full activity. Martin said he was grateful the Dodgers forced him to rest. While acknowledging he agreed with manager Dave Roberts' assertion that he can afford to be down a week, he emphasized the importance of working with every pitcher to establish chemistry and communication. "I definitely want to be on the field as much as possible because there are a lot of guys I haven't really had the chance to work with," he said. Kershaw is the only Dodgers pitcher who is still on the roster from 2010, the last time Russell played for the Dodgers. ... LHP Rich Hill pitched 4 2/3 innings in a minor league game to stretch to five innings and 75 pitches. He struck out four his last five batters. ... SS Corey Seager batted second in three consecutive innings of the same game, with a groundout, a sharply hit flyout and a called strikeout.___More AP MLB: https://apnews.com/tag/MLB and https://twitter.com/AP_Sports