Club source: Giolito and Lopez joining high Single-A Potomac (updated)

Two of the Nationals' top right-handed pitching prospects, Lucas Giolito and Reynaldo Lopez, will officially join high Single-A Potomac this week, a high-ranking club source confirmed to MASNsports.com.

The duo has been working out and logging innings at the Nationals training facility in Viera, Fla., over the past month. Giolito and Lopez's first starts with the P-Nats are imminent, and will be announced this week.

Potomac's published game notes list "TBA" for Wednesday night's scheduled starter against Wilmington. That spot could potentially be filled by either Lopez or Giolito.

Giolito is No. 7 and Lopez No. 49 on Baseball America's Top 100 prospects list.

They are also No. 1 and No. 3, respectively, on the Nationals' top prospects 10 list. Giolito, a 2012 first-round selection, tossed 98 innings last season for low Single-A Hagerstown, going 10-2 with a 2.20 ERA and recording 110 strikeouts. Lopez went 5-1 with a 0.63 ERA in his final 10 starts between short-season Single-A Auburn and Hagerstown, notching 52 strikeouts to only 14 walks.

It would be expected that Giolito and Lopez would most likely stay around five innings and 75 pitches per start. The Carolina League competition is a step up from the South Atlantic League and would be a good test for the pair who did so well in low Single-A in 2014. They are both healthy and in good shape, and no other limitations will be placed on their starts.

Update: The Potomac Nationals officially announced that Giolito and Lopez have joined the team from extended spring training. They are working out during pregame activities at Pfitzner Stadium. Their first games have not been announced but the P-Nats Web site list "TBD" for their starting pitchers Wednesday and Friday. Giolito will wear jersey No. 23. Lopez will wear jersey No. 14.

Update II: The P-Nats game notes have Lopez listed as the probable starter Wednesday night and Giolito to make his Potomac debut Friday night.