Time to finalize the 40-man

Over the last week, we've seen the Nationals make a couple of moves that cleared up space on the team's 40-man roster.

Left-hander Matt Purke was released, and then subsequently re-signed to a minor league contract. That series of moves opened up a spot on the 40-man.

On Tuesday, catcher Jhonatan Solano was also released, leaving the Nats with 38 players on their 40-man roster.

And with today being the reserves deadline - the last chance for teams to add minor leaguers that are eligible for the Rule 5 draft to their 40-man rosters - we could still see another move or two.

As a refresher, players who were signed when they were 19 or older and have played in professional baseball for four years are eligible for the Rule 5 draft, as are players who were signed at 18 and have played for five years.

The Nationals have a few such prospects whose names many fans will recognize.

Right-hander A.J. Cole, who was a fourth-round pick of the Nats back in 2010 and is considered the organization's No. 2 prospect, is Rule 5-eligible this year. Cole, 22, posted a 3.16 ERA between Double-A Harrisburg and Triple-A Syracuse last season, and could potentially make it t the big leagues at some point in 2015. He will definitely be added to the 40-man.

Brian Goodwin, a first-round pick in the 2011 draft, is also eligible. Goodwin was once considered the Nats' center fielder of the future, but his stock has slipped a bit recently, and he hit .219/.342/.328 at Syracuse this season.

First baseman/third baseman Matt Skole, a fifth-round pick in 2011, is another player who will be up for the Rule 5 draft this year. Skole came back from Tommy John surgery to post a .241/.352/.399 line with 14 homers at Harrisburg in 2014.

Add left-handed reliever Matt Grace, an eighth-round pick in 2010, to the list, as well. Grace has excelled the last few seasons since being converted to a full-time reliever, and he had a tremendous 2014 split between Harrisburg (1.02 ERA in 35 1/3 innings) and Syracuse (1.30 ERA in 41 2/3 innings). The 25-year-old could be in the mix for a spot in the Nats bullpen this spring, if he is protected or isn't selected in the Rule 5 draft.

One catch when it comes to players taken in the Rule 5 draft is that they must remain on the selecting team's big league roster all season or be offered back to their previous organization. Therefore, teams sometimes leave a Rule 5-eligible player off their 40-man intentionally if he is lower on the organizational depth chart, taking a chance that a player without experience at Double-A or Triple-A won't stick on a selecting team's major league roster for a full year.

Infielder Wilmer Difo could fit into that category. The 22-year-old Difo had a tremendous 2014 season at low Single-A Hagerstown and was named the Nationals' minor league Player of the Year after hitting .315/.360/.470 with 14 homers, 90 RBIs and 49 stolen bases in 58 chances.

Fantastic numbers, clearly, and talent evaluators both inside and outside the organization are very high on Difo, seeing him as one of the Nats' top infield prospects. But given that Difo has only played six games above low Single-A ball in his professional career, the Nationals might leave him off their 40-man roster, taking a chance that he either won't be selected in the Rule 5 draft - or, if he is, that Difo wouldn't make it through a full season on a big league roster.

It would be a risky move, given the Nats' lack of infield prospects. But if the Nationals don't feel they can clear enough space on the 40-man to protect everyone they like, they could roll the dice and leave the talented but raw Difo unprotected.

As of right now, the Nats have two open spots on the 40-man. Will they clear more? Who will they protect?

We'll see how things play out.