By MARK SIMON

Oakland Athletics third baseman Matt Chapman is the Sports Info Solutions Defensive Player of the Month for March and April.

The selection was made based on voting by a panel comprised of members of SIS' Research & Development department and Operations staff, as well as longtime baseball writer Jayson Stark. We'll be picking a player each month for the duration of the season.

Chapman beat out Indians third baseman Jose Ramirez and Braves right fielder Nick Markakis for the honor after ending the month with five Defensive Runs Saved (tied with Travis Shaw and Ramirez for the lead at third base) and nine Good Fielding plays (tied with Nolan Arenado for the positional lead).

The bigger question here may be whether Chapman can stake a claim to being the best defensive third baseman in the game.

Rockies third baseman Nolan Arenado has been the standard-setter at the hot corner, winning the last three Fielding Bible Awards, but since the start of last season, Chapman has him beat.

Chapman has saved 24 runs defensively in 978 innings since his recall. Arenado has 20 Defensive Runs Saved in nearly 600 more innings since the start of 2017. They're No. 1 and No. 2 in that span (the chart below lists the leaders through April 30).

How impactful has he been?

In looking at the impact that Chapman has made on the Athletics defense, look at a play like the one linked here, and consider this:

Our defensive charting allows us to look at ground ball and bunt out rate for any area of the field. In this case, the area we're concerned with is from the third base bag to about one-third of the way to second base.

Last season, prior to Chapman becoming their everyday third baseman on July 3, the Athletics converted 66 percent of ground balls in that area into outs. That ranked 24th in the majors.

Since July 3, 2017, the Athletics have converted 75 percent of those grounders into outs. That ranks third in the majors. When you do the math, the difference from last season to this season comes out to about 27 more out conversions on ground balls since Chapman's move into the lineup.

Perhaps not coincidentally, the Athletics are a better all-around team in the infield. Their infield has saved 13 runs defensively so far this season, compared to their defense costing the team four runs in 2017.

The Athletics have floundered in recent seasons, but went 57-54 in Chapman's first 111 starts. His impact in the field has been considerable all around.

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Ramirez had a great defensive month for an Indians team that led the majors in groundball out rate through the end of April. He finished the month with five Defensive Runs Saved, keyed by the majors’ highest success rate converting outs on balls down the line. His only Defensive Misplay came on the final day of the month.

Markakis led all right fielders by saving six runs defensively through the end of April. Those runs were evenly split among range and positioning, the deterrent value of his throwing arm and Good Fielding Plays. Notably, Markakis had three assists without the help of a cutoff man, more than halfway to the five he recorded in each of the last two seasons.