Now that Seranthony Dominguez has responded to the challenge of getting called up to the big leagues by doing something that no pitcher since 1908 — and maybe ever — has accomplished, there's one big question about the Phillies rookie sensation that remains unanswered.

How often can he pitch?

Dominguez was a starter from the time the Phillies signed him out of the Dominican Republic as a 17-year-old in 2011 until the day last offseason that they informed him he was being converted to a reliever in the minors. While the new role requires plenty of adjustments, the trickiest thing might be figuring out how much recovery time a novice reliever needs between outings.

Considering Dominguez became the only reliever in at least 110 years to not allow a hit or a walk in his first six major-league appearances before finally giving up a single Monday night, it must be tempting for the Phillies to call on him as often as possible. But they will closely monitor his usage in an effort to make sure he can handle the workload.

"I think that we'll really watch him," pitching coach Rick Kranitz said. "If he pitches today, he's off tomorrow more than likely. He's going to say he's ready to pitch every day. But we need to protect him."

Dominguez appeared on back-to-back days once in the minors (April 23-24 at double-A Reading), but usually received at least one day of rest. The Phillies used him on back-to-back days on May 9-10 against the San Francisco Giants, although he threw only eight pitches in the first of those appearances. Ideally, manager Gabe Kapler said he'd like to be able to use Dominguez twice in every three-game series.

Kapler has already demonstrated a willingness to put Dominguez in the highest-leverage situation of a game. Last Thursday night, Dominguez entered with two on, one out and the Phillies leading by one run in the seventh inning against the St. Louis Cardinals. On Monday night, he faced the top of the Atlanta Braves' lineup — Ozzie Albies, Ronald Acuna Jr. and Freddie Freeman — in the eighth inning of a three-run game.

"If I was going to bet on anybody, just based on youth, athleticism, body type, I'd probably bet on him to be able to handle that kind of stress," Kapler said. "But we're going to err on the side of being slow with it and seeing how he responds to pitching and then a day off and then pitching."

Right stuff for Williams

After taking a back seat to Aaron Altherr for most of the season's first quarter, right fielder Nick Williams started for the fifth time in seven games Tuesday night. Kapler cited Williams' recent offensive surge (.943 OPS in 31 plate appearances through Monday) as the reason for the shift in playing time.

With lefty Luiz Gohara starting for the Braves on Wednesday night, Kapler said righty-hitting Altherr will be in the lineup.

Extra bases

In the last series between the Phillies and Braves, a three-game set on April 27-29 at Citizens Bank Park, Atlanta stole eight bases, five of which came with Jorge Alfaro behind the plate. Since then, Alfaro has thrown out six of 10 attempted base stealers. “Our expectation is that [opponents] understand what we have in Alfaro,” Kapler said. … The Phillies entered Tuesday night with the best home record in baseball (17-6). But they ranked 11th out of 15 National League teams in total attendance (585,748).