A few weeks ago we learned the dimensions of the ballpark for the upcoming London Series. The all-purpose London Olympic Stadium is going be set at the following dimensions:
Home plate to the foul poles – 330 feet (100 m)
Home plate to centre field – 385 feet (117 m) with a 16-foot (4.9 m) fence in place.
The dimensions have been described as being potentially hitter-friendly in various sources, including our own podcast where they were choosing the over and under line in the double figures. But is this field really going to be that hitter friendly? Let’s analyse some figures to work this out.
So far in 2019, MLB teams average 1.36 home runs per game which is the highest figure for a season ever (currently surpassing 2017’s record of 1.26). But we cannot describe either the Yankees or Red Sox as average in this department. The Yankees have been hitting them a clip of 1.64 per game and the Red Sox at 1.41. So, if this was an average two game series between these two teams we would expect around 6 homers to be scored.
We know this isn’t a standard game and venue but let’s work from 6 expected home runs and determine if we should move it up or down depending on other factors. Before we look at the impact of the stadium lets look at the expected pitchers and bullpens of both the teams to see if we expect more or less home runs because of them.
Yankees
Masahiro Tanaka: Career HR/9 – 1.32, 2019 HR/9 – 1.19
Throughout most of his career, Tanaka has had an above league average home run rate. So far in the juiced ball 2019 season he has been below the average.
According to Lindsay Adler the Athletic’s Yankees reporter we should be expecting an opener/bullpen game on the Sunday game. We were thinking it was going to J.A. Happ but his continued struggles mean the Yankees have decided against him starting.
If they go for the opener approach we should expect to see Chad Green start, he has done so on seven occasions already this season. With the last four having, rookie, Nestor Cortes Jr. picking up the bulk of the innings afterwards. In those 7 games, Green has given up 2 home runs across 10.2 IP and in his four appearances after Green, Cortes has given being taken deep twice over 15.1 IP.
Rest of the Bullpen: 2019 HR/9 – 1.37
The Yankees bullpen have been good this season but not the best bullpen like they had been over the two previous seasons. The injury to Dellin Betances which has stopped him pitching so far in 2019 has meant that more innings have been given to their lesser relievers. Aroldis Chapman, Adam Ottovino and Zack Britton all have great K rates and low HR/9 rates but Jonathan Holder and Tommy Kahnle have both given up bombs at an alarming rate.
Overall rating: Across the two days i can see these coming out fairly even to projections, so I won’t adjust the project rate for the Red Sox. That being said I would expect to see more home runs in the game when the opener happens than when Tanaka starts.
Red Sox
Rick Porcello: Career HR/9 – 1.09, 2019 HR/9 – 1.15
Porcello has pitched close to his career average home run rate this season and in the home run heavy scenario we have had in 2019, that gives me confidence in saying that he shouldn’t be the one giving up the home runs. We might see balls in play, as he doesn’t strike many out, but don’t expect many home runs.
Eduardo Rodriguez: Career HR/9 – 1.21, 2019 HR/9 – 1.46
Rodriguez’s number’s for 2019 follow closely to the overall MLB trend. He looked good at the start of the season giving up just four HR in his first nine starts but in his seven starts since he has given up 11, including two in his last two games.
Bullpen: 2019 HR/9 – 1.19
With how the season has gone so far, if I was to tell you that the Red Sox bullpen have had a better ERA, FIP, K% and HR/9 than the Yankees bullpen you might not believe me. However, it is true.
Like the Yankees they have a softer underbelly but Matt Barnes, Ryan Brasier and Brandon Workman have pitched well despite some high profile blown saves.
Overall rating: As with the Yankees there isn’t much to change expectation here, Rodriguez could get blown up but Porcello and the bullpen should keep the Bronx Bombers in check.
Based of the players who we should see in London this weekend we should expect about 6 home runs. So, lets get to the elephant in the room. The dimensions of the stadium.
The MLB rulebook states that parks constructed by professional teams after June 1, 1958, must have a minimum distance of 325 feet between home plate and the nearest fence, stand or other obstruction on the right- and left-field foul lines, and 400 feet between home plate and the nearest fence, stand or other obstruction in centre field.
However, some clubs have been permitted to construct parks after that date with dimensions shorter than those specified and the London Stadium’s dimensions are good with regards with the distance to the foul poles but falls a bit short in centre field. The picture below shows the dimensions for the 30 major league parks. (Click the link to expand it)

The 385 feet to straightaway centre is five feet shorter than the shortest, which is at Boston’s Fenway Park. There are a further three (Giants, Dodgers & Padres) which are less than 400 feet but all of these have a shorter fence than the 16 feet we will see at centre in the London Olympic Stadium. Most MLB ball parks have their centre field fences at 400 feet with a 8-10 feet high fence. The height of the fence actually means that it will play deeper than 385 feet.
Using renowned baseball physicist Alan Nathan’s baseball trajectory calculator, a 16 feet wall at 385 feet plays similar to a 8 feet wall at 395 feet. So, we really shouldn’t expect any more home runs to straightaway centre than normal.
If we look at all distance to the foul poles, London is deeper in both directions than Yankee Stadium and Fenway Park. The exception here being the Green Monster at Fenway which might only be 310 feet out from home plate but stands at 37 feet tall.
These park dimensions don’t suggest that much of a difference from a major league ballpark, the fence at centre has taken care of that.
The other thing you might have noticed about the London set up is the large swathes of foul territory which draw comparison to one MLB stadium in particular, Oakland’s Coliseum.

The Coliseum is widely regarded as a pitching stadium, the enlarged foul territory means that more foul balls can be caught by the fielding teams. This should come into play in this two game series.
Overall I think this stadium will play much more like a standard MLB stadium than most people have been talking about. While I would expect there to be around 6 home runs that doesn’t mean it is beyond the realms of possibility that we could see 10+. Just put it in the unlikely category.