BALTIMORE—The Orioles purchased the contract of infielder Dilson Herrera from their alternate site at Bowie and recalled outfielder DJ Stewart from Bowie on Tuesday.

Herrera, who was signed as a minor league free agent last December, has a .203 lifetime batting average with 11 home runs and 23 RBIs in 102 major league games with the New York Mets in 2014 and 2015 and Cincinnati in 2018.

Stewart, the team’s No. 1 draft choice in 2015, began the season with the Orioles but was sent to Bowie when the rosters were reduced from 30 to 28 on August 6th. He was hitless in 15 at-bats with eight strikeouts, though he did walk six times.

Herrera was added because Hanser Alberto suffered a knee injury running out a drag bunt to first base in the 10^th inning of Monday’s 4-3 11-inning victory over the Toronto Blue Jays that ended a five-game losing streak. Alberto will likely miss  the two-game series with the Mets that begins Tuesday night at Camden Yards.

“Kind of hurt it jamming it into the base,” manager Brandon Hyde said. “He felt some knee soreness, and didn’t finish the game. Today, he does feel better, and we’re encouraged by that, but he definitely is day-to-day. We’re not sure he’s going to be able to play this series.”

The Orioles have an offday on Thursday before they play a doubleheader against the New York Yankees on Friday.

“DJ has been swinging the bat very well at our secondary site,” Hyde said. “We wanted to see him get back up here, and he’s going to be in the mix. I want to get him in the lineup. Another young player that we need to find out more about.

“We’ve got to get him some more at-bats. That’s why he’s here. He got here today, and I’m going to try to get him in the lineup.”

To make room on the roster, the Orioles designated outfielder Mason Williams for assignment. Williams was hitting .182 (2-for-11).

“Mason was kind of covering us a little bit for [Ryan] Mountcastle with Mountcastle’s inexperience defensively, and I think Ryan is starting to get a lot more comfortable in left field. You’ve seen that the last couple of days. It was more about getting DJ here than anything else.”

The Orioles have 38 players on their 40-man roster and 57 in their 60-man player pool.

Centerfielder Austin Hays, who has been on the 10-day injured list since August 15th because of a rib fracture, should begin baseball activities in the next few days.

“Feeling much better,” Hyde said. “Hopefully, on the track to join us sometime in the next two weeks.”.

First baseman Chris Davis, who’s on the IL because of left knee injury, is still resting, Hyde said.

What’s with players to be named later: The trading deadline is over, and since the season began, Orioles executive vice president/general manager Mike Elias has made five trades, which netted three known players — left-handed pitcher Kevin Smith from the New York Mets for Miguel Castro, and infielders Tyler Nevin and Terrin Vavra from the Colorado Rockies, who were obtained for Mychal Givens.

Elias received six players to be named later, although the number might be reduced to five because the Mets agreed to a player to be named later or cash.

Fans might be confused about the players to be named later because in the past they equated to low-level prospects who rarely amounted to much. That could still be the case, but this year it’s much different.

Nevin, Smith and Vavra were identified because they were at their team’s alternate sites as part of their 60-man player pools, and they’ll be going to Bowie, the Orioles’ alternate sites.

In 2020, players can only be traded for others who are part of the 60-man player pool.

Players who aren’t part of the 60-man pool can’t be identified.

“Those names will be named at the appropriate time,” Elias said in a video conference call on Sunday night.

“Obviously, there are some strange restrictions in place this year. You’re seeing an uptick in player-to-be-named later trades. I think you can draw your own conclusions about why, but I’m looking forward to naming those mystery players at some point and, hopefully, welcoming them to the organization.”

Because only 32 players can be at an alternate site, a large number of desirable prospects can’t be brought to camp.

The Orioles don’t have a number of top prospects in camp because there simply isn’t room. Pitchers Gray Fenter, Blaine Knight, Zac Lowther, Drew Rom and Alexander Wells aren’t at the alternate site. Nor is Heston Kjerstad, this year’s top draft choice.

Nevin, Smith and Vavra are on lists of top prospects, and so might some of the others who were obtained in trades. They just haven’t been invited to teams’ alternate sites.