PITTSBURGH -- Already faced with a potential roster crunch in the middle infield, the Pirates on Friday added another option to their Spring Training competition by signing former Nationals infielder Wilmer Difo to a Minor League contract.

The 28-year-old Difo’s pact includes an invitation to big league Spring Training camp. The club is expected to announce more Spring Training non-roster invitees in the coming days.

Difo spent parts of the last six seasons with the Nationals, hitting .247/.309/.348 with 15 homers and 79 RBIs in 1,060 plate appearances over 373 games. The switch-hitter’s best season came in 2017, when he posted 1.5 wins above replacement while batting .271 with a .690 OPS, 10 steals and nine defensive runs saved at shortstop. He played in only 12 games for Washington last year before he was outrighted to the club’s alternate training site on Sept. 7.

Difo does offer defensive versatility, as he’s made 154 appearances (107 starts) at second base, 108 appearances (89 starts) at shortstop and 37 appearances (30 starts) at third base while appearing briefly in all three outfield spots in the Majors. That could give him a chance to crack the Pirates’ Opening Day roster, but they already have likely starters at three infield spots -- first baseman Colin Moran, second baseman Adam Frazier and third baseman Ke’Bryan Hayes -- plus a handful of utility-type options in Phillip Evans and their three shortstop candidates: Kevin Newman, Erik González and Cole Tucker.

There is still the possibility that Frazier, one of nine arbitration-eligible players who agreed to terms on contracts for the upcoming season on Friday, and others could be traded before the start of the season. Moving Frazier, for instance, would create two infield spots for the Pirates' three shortstop candidates. Evans could be a natural platoon partner for Moran at first and a potential backup for Hayes at third. Further moves or injuries could create a path to playing time for Difo.