Paulsen, 28, entered Friday with a .300 average against lefties over parts of three Major League seasons -- but in just 50 at-bats.
"When I've been up here, there's been situations where guys hit lefties better than I do," Paulsen said. "I went down there, and that was the first time in a year and a half that I got to face lefties on a regular basis.
"I took it personally. That was the thing G-Hill talked to me about. 'You should hit lefties as well as you do righties.'"
The Rockies will need for Paulsen to play the position regularly, since he is the only true first baseman on the roster. And with a lineup of at least five lefty hitters, they'll need players who can handle all matchups.
"At the Minor League level, it's less specialized, so left-handed hitters get a lot of at-bats against left-handed pitchers," Rockies manager Walt Weiss said. "It's going to help. We're pretty left-handed right now, and that's OK. We have some pieces we can move around.
"Benny always seems to rise to the occasion."
Utility man Daniel Descalso has performed admirably at first and in left field, but he'll be needed at shortstop because Trevor Story's left thumb surgery will likely cost him the rest of the regular season. Right-handed hitting outfielder Ryan Raburn, once a second baseman, has always carried a first baseman's glove with him and worked out there Friday, while switch-hitting middle infielder Cristhian Adames took some throws at first Friday.
Reynolds out 4-8 weeks
Reynolds, 33, who signed a one-year deal worth $2.6 million before the season, was hitting .283 with 12 home runs and 50 RBIs in 106 games and demonstrating control with the bat.
"He's evolved as a hitter later in his career; you saw that trend maybe a year or two ago," Weiss said. "There used to be a lot of all-or-nothing with Mark -- a lot of raw power, but a lot of swing-and-miss, a lot of empty at-bats. He's gotten away from that. We see him using the entire field, and he's beat the shift a lot this year.
"The bottom line is he's a tougher out than he used to be."
Top prospect's bat travels
Brendan Rodgers, the Rockies' No. 1 prospect according to MLBPipeline.com, has hit a solid .277 with a .343 on-base percentage, 15 home runs and 61 RBIs at Class A Asheville while playing shortstop (47 games) and second base (21). Rockies player development director Zach Wilson said he isn't pinning Rodgers to a position, but the bat plays anywhere.
"Right now he's a middle infielder. That's the best way I can describe it," Rodgers said. "He's got a chance to stick at short, absolutely. But I think it's important, especially for a kid who is advanced defensively, to start to introduce repetitions at the other infield spots. We've started with second base, and he's done very well."