The Nationals announced that they have selected the contract of top shortstop prospect Trea Turner to the Majors.In order to clear a spot on the active roster, the Nationals have placed Tyler Moore on the disabled list. Meanwhile, righty Aaron Barrett will hit the 60-day DL to clear a 40-man spot.

With the move, Washington has added its best position-player prospect for the stretch run. The team previously called up fellow middle infielder Wilmer Difo, but used him only sparingly and decided this time to give the nod to Turner.

This move seems more significant than the Difo call-up, because Turner did not need to be added to the 40-man after the season. Giving him a roster spot now means that the club has one less opening to protect other assets from the Rule 5 draft. It’s certainly possible that Washington decided it could get by without the extra space, but the move might also suggest that the club feels Turner can contribute down the stretch and/or make a viable challenge to take over for pending free agent Ian Desmond to open the 2016 season (in which case it might be valuable to give Turner a look at the bigs this year).

Turner came to the Nats along with right-hander Joe Ross in the three-team trade that sent Steven Souza to the Rays and Wil Myers to the Padres. He now joins Ross as part of the organization’s 25-man roster, a fact which reflects better on the trade than it does the team’s overall performance this year.

Since the deal, Turner has done nothing but enhance his value. He’s now a consensus top-20 prospect leaguewide, if not better, after dominating at Double-A and putting up a strong .314/.353/.431 slash with 14 steals in his first 205 plate appearances at the highest level of the minors.

While his first-round draft status and rising stock have elevated Turner’s profile, he is probably still best known for being dealt as the player to be named later in the aforementioned trade. The two sides used a loophole in a since-changed rule that stated a player could not be traded until one year after he is drafted. San Diego took Turner 13th overall in the 2014 draft, and they took advantage of the fact that teams can take up to six months to determine a PTBNL to trade him in December. Of course, that meant that Turner, who had been widely reported as the PTBNL, spent Spring Training and the first three months of the season with the Padres despite the fact that everyone knew he’d been traded to the Nationals. This was far from the first occurrence of PTBNL manipulation, but it was perhaps the most public example, and it spurred the league to take action and amend the rules so that players can be traded upon completion of the World Series in the year they are drafted.