Source: Nats promoting top prospect Carter Kieboom (updated)

Carter Kieboom, the Nationals' top prospect off to a red-hot start at the plate with Triple-A Fresno, is getting called up to make his major league debut this weekend, a source familiar with the move confirmed.

It's not yet clear what corresponding transaction (or transactions) will be made before Kieboom's contract is purchased. The Nationals not only need to remove someone from the active, 25-man roster but also to clear a spot on the 40-man roster for Kieboom, the organization's first round draft pick in 2016.

The Washington Post first reported Kieboom's promotion.

Kieboom was off to a torrid start with Fresno, hitting .379 with three homers, 18 RBIs, a .506 on-base percentage and a 1.142 OPS in 18 games. The 21-year-old has played 12 of those games at shortstop (his natural position) and six games at second base (the club's more likely long-term position of need).

General manager Mike Rizzo historically has only promoted top prospects if he intends to play them on an everyday basis, and Kieboom's promotion shouldn't be an exception. Which suggests Kieboom is likely to take over as the Nationals' starting shortstop until Trea Turner returns from a broken right index finger.

Turner, who suffered his injury 23 days ago, has been participating in some baseball activities but has not yet been cleared to throw or hit, manager Davey Martinez said earlier this week in Denver. The club has offered no timetable for Turner's eventual return, but he was seen wearing a brace on his hand and talking with Rizzo on Wednesday in the visitors' clubhouse at Coors Field.

Wilmer Difo has started every game at shortstop in Turner's absence. He's hitting .246 with two homers, six RBI and a .678 OPS. He also committed a costly error this week against the Rockies and also was blamed by Martinez for not making a play on a pop-up down the third base line that fell between himself and rookie third baseman Jake Noll.

The Nationals not only have been playing without Turner but for the last four games also without third baseman Anthony Rendon, who was struck by a pitch in his left elbow Saturday in Miami. Though Martinez said Rendon has been making steady progress each day and said he was available to pinch-hit Wednesday afternoon, the star third baseman has historically been a slow healer. If he's not ready to return to the lineup by Friday, the club may have no choice but to place him on the injured list.

That would clear up a spot on the 25-man roster for Kieboom, but it wouldn't clear a spot on the 40-man roster. In order to do that, the Nationals either need to transfer an injured player to the 60-day IL or designate a player for assignment. Veteran reliever Trevor Rosenthal, who has a 36.00 ERA in seven cringe-worthy appearances, could be facing his own roster decision in the coming days.

Update: Noll is in the lineup for Fresno tonight, playing second base and batting sixth at Reno. So that would appear to be the corresponding 25-man roster move.